public OnPluginStart() HookEvent("round_start", Round_Start);

public Round_Start(Handle:event, const String:name[], bool:dontBroadcast)
{
       new team_T;
       for (new i = 1; i <= MaxClients; i++)
       {
               if (IsClientInGame(i) && GetClientTeam(i) == 2) team_T++;
       }
       PrintToChatAll("Террористов: %d", team_T);
}