function Main(arg) {
    let n = Number(arg.trim());
    let result = '';
    while(n > 26) {
      let tmp = n / 26;
      result = String.fromCharCode(n % 26 + 96)  + result;
      n = tmp;
    }
    result = String.fromCharCode(n % 26 + 96)  + result;
    console.log(result);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));
