Help with derby PLEASE

Hello! I made derby (over the water), but i don't know how to give prizes to first and second survivor! I made VehicleIsInWater and to join command i added DerbyPlayers += 1;, but tell me how to check if the player is last surviror and if player is second survivor?
+1 REP, who help me :)

SRY ABOUT MY BAD ENGLISH!!!