By Simon Smale, ABC
Watching the Olympic Games often boils down to understanding who is representing whom in each event.
The International Olympic Committee (IOC) has a helpful code of acronyms that it uses to help determine who is who.
Most of the time these codes are pretty obvious: AUS is the three-letter code that represents Australia, PNG is Papua New Guinea, NZL is New Zealand, for example.
Others can be slightly more confusing: CHI relates to Chile while CHN is China, and Moldova is MDA with the Maldives represented by MDV.
Even more confusingly, the IOC lists Bahrain as BRN, which is what the International Organization for Standardization (ISO) uses for Brunei (BRU according to the IOC).
But then there are others that are understandably quite hard to work out, such as AIN - because that's not a country at all.
What is the AIN at the Paris Olympics?
AIN stands for Athlètes Individuels Neutres, which in English is Individual Neutral Athletes.
The AIN is the name used to represent approved Russian and Belarusian athletes at the 2024 Summer Olympics.
Those athletes are banned from using the neutral Olympic flag and Olympic anthem, which has been used in the past for neutral athletes.
It will, instead, use a flag depicting a circular AIN emblem and a one-off instrumental anthem that has been assigned by the IOC.
AIN must be approved by each sport's international federation, but even if an athlete meets the qualification criteria, the sport has the discretion to not give them a spot.
The group cannot take part in the opening ceremony along the Seine.
Because the AIN is not a team, any medals that are won by AIN athletes will not be grouped together on the overall medal table.
What Russian or Belarusian athletes are eligible?
The IOC convened a three-person panel to rule on which athletes would be allowed to compete: consisting of IOC vice-president, former Aruban artistic swimmer Nicole Hoevertsz, ex-NBA star Pau Gasol from Spain, and South Korea's Olympic table tennis champion Seung Min Ryu.
The "principles of participation" state that only athletes who have "not acted against the peace mission" of the IOC "by actively supporting the war" will be invited.
No teams will be allowed to be formed involving athletes at the Games, including relays.
No Russian or Belarusian government or state officials will be invited or accredited "in any capacity" at the Games.
Some athletes have refused the invitation to take part as neutrals.
The Russian wrestling federation said in a statement in July that the 10 athletes that had been invited to compete, plus officials and coaches, "came to a unanimous decision - to refuse to participate in the Olympic Games".
The 2021 US Open champion, Daniil Medvedev, is among six tennis players who the IOC says have accepted an invitation.
Andrey Rublev, Karen Khachanov, Aryna Sabalenka and Victoria Azarenka are among the big tennis names who declined their invitation.
Weren't Russia called something else in Tokyo?
That's right.
In Tokyo in 2021 and at the 2022 Winter Olympics in Beijing, Russian athletes competed under the moniker ROC.
ROC stands for Russian Olympic Committee, and Russian athletes were allowed to represent the committee, even though they could not represent their own country.
Why couldn't they compete as Russia in those events?
Russia was banned for repeated doping violations by the World Anti-Doping Agency (WADA) in late 2019.
Why are Russia and Belarus banned from this Olympics?
Russia and Belarus were banned by the IOC upon the invasion of Ukraine in February 2022 - just after the conclusion of the Winter Olympics.
The IOC mandated that athletes from those two countries should be allowed to compete as neutrals as long as they did not support the war and did not wear any national colours, names, flags or anthems - ruling out the use of ROC.
The IOC introduced the option for athletes from those countries to compete as individuals under the AIN in March 2023.
In September 2023, WADA issued another ban on Russia due to more failings relating to anti-doping measures.
Then, in October, the IOC issued yet another ban on Russia for breaching the Olympic Charter by annexing the Olympic Councils of Kherson, Zaporizhzhia, Donetsk, and Lugansk into the Russian Olympic Committee.
Is this controversial?
You betcha.
Despite the organisations being banned, some Ukrainian officials have said no athletes from Russia or Belarus should be allowed to compete at all, even as neutrals.
The IOC said in its "statement on solidarity with Ukraine" in January 2023 that: "No athlete should be prevented from competing just because of their passport."
Ukraine countered, saying that the IOC had no such qualms about banning athletes with South African passports during the apartheid regime that saw South Africa banned from competing from 1964 until 1992.
There has also been lots of discussion about whether Israeli athletes should also be banned following the conflict in Gaza, with petitions massing hundreds of thousands of signatures.
Have there been other instances of individuals competing at Olympic Games?
There have.
In 1992, athletes from the Federal Republic of Yugoslavia were allowed to compete under the banner of Independent Olympic Participants (IOP).
Yugoslavia has been hit by United Nations sanctions as a result of the war taking place in the country, which led to Yugoslavia being banned from sending a team to the 1992 European Football Championships.
Incidentally, their last-minute replacement, Denmark, ended up winning the entire tournament.
The flag it flew, the IOP banner (the Olympic rings on a white background) was dusted off again for the 2014 Sochi Winter Olympic Games to allow three Indian athletes to compete while the Indian Olympic Committee was suspended due to government interference and corruption allegations.
Also in 1992, the Unified Team (EUN) was used to represent athletes from the former Soviet Union.
IOA has also been used regularly since 2000, first for athletes from Timor-Leste in Sydney, then in 2012 for athletes from South Sudan and the Netherlands Antilles.
The IOA was used in Rio in 2016 as well, this time for athletes from Kuwait.