import java.util.Scanner;

public class Main {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    long n = sc.nextLong();
    String alphabet = "abcdefghijklmnopqrstuvwxyz";
    String name = "";
    while(n > 0){
      n--;
      long remain = n % 26l;
      name = alphabet.charAt((int)remain) + name;
      n = n / 26l;
    }
    System.out.println(name);
  }
}
/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