

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();
        String tmp = "";

        while(N>0) {
            --N;
            tmp += (char)('a' + (N%26));
            N /= 26;
        }
        StringBuffer sb = new StringBuffer(tmp);
        String res = sb.reverse().toString();
        System.out.println(res);
    }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz