The Iwatobi Swim Club needs one more member before it can participate in relays.  Nagisa has set his sights on his classmate Rei, who is a member of the track team.  Despite Rei's refusal to join, but Nagisa appears intent on recruiting Rei into the swim club.
Besides, we can't swim a 
relay with three people.
Außerdem können wir mit drei Leuten keine Staffel schwimmen.
Además, no podemos hacer 
un relevo con 3 personas.
Además, no podemos competir 
por relevos con solo tres personas.
Et puis d’abord, on ne peut pas 
faire de relais à trois.
In ogni caso, tre persone non bastano.
Além disso, não dá para fazer revezamento 
com somente três pessoas.
Да и вообще, в эстафете втроём
не участвуют.