function Main(input) {
  const n26 = parseInt(input, 10);
  const n26Str = n26.toString(26);

  const alp = "abcdefghijklmnopqrstuvwxyz";

  const name = n26Str.replace(/./gi, function (str) {
    return alp[parseInt(str, 26) - 1];
  });

  console.log(name);
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));
