import java.util.*;
public class Main {
    static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) {
        long n = sc.nextLong();
        String res = "";
        while(n > 0){
            char c = (char)((n % 26 == 0 ? 26 : n % 26) - 1 + 'a');
            res = c + res;
            if(n % 26 == 0)
                n = n / 26 - 1;
            else
                n/= 26;
        }
        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