SFY

var steamId64 = 76561198032122624;
var universe = (steamId64 >> 56) & 0xFF;
if (universe == 1) universe = 0;
var accountIdLowBit = steamId64 & 1;
var accountIdHighBits = (steamId64 >> 1) & 0x7FFFFFF;
var legacySteamId = "STEAM_" + universe + ":" + accountIdLowBit + ":" + accountIdHighBits;