[Isolated]

pawn Код:

GenerateRandomLetters(len) {
    new Letters = ['A','B','C','D','E','F','G','H','I','J','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'];
    new Ret[len];
    for(new i = 0; i < len; i++) {
        format(Ret, sizeof(Ret), "%s %s", Ret, Letters[i]);
    }
    return Ret;
}

Something like this - untested - I'm a PHP developer, may be a little wrong.