import java.util.*;
class Main {
  	static Scanner scan = new Scanner(System.in);
  	public static void main(String[] args) {
  		long N = scan.nextLong();
    	System.out.println(dogName(N));
  	}
 	private static String dogName(long N) {
    	String ans = "";
      	long temp = N;
      	while(temp > 0) {
            temp--;
            long rem = (temp % 26);
        	char cc = (char)('a' + rem);
          	ans = cc + ans;
          	temp /= 26;
        }
       return ans;
 	}
}
/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