var steamID64 = 76561198030676795;
var accountID = steamID64 - 76561197960265728;
var steamID = function(accountID) {
    if (accountID % 2 == 0) {
        return "STEAM_0:" + "0" + (accountID/2).toString();
    } else {
        return "STEAM_0:" + "1" + (accountID/2 - 0.5).toString();
    }
};