import java.util.Scanner;

public class Main {
   public static void main(String[] args) {
       Scanner s = new Scanner(System.in);
       long n = s.nextLong();
       int rem=0;
       String name = "";
       char c;
       while(n>0) {
           rem =(int) ((n-1) % 26);
           c = (char)('a'+rem);
           name+=c;
           n= (n-1) /26;
       }
       for(int i=name.length()-1;i>=0;i--) {
           System.out.print(name.charAt(i));
       }
   }
}

/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