
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
 
public class Main {    
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        long n = Long.parseLong(sc.next());
        String[] list = new String[26];
        char temp = 'a';
        for(int i=0;i<26;i++){
            list[i] = String.valueOf(temp++);
        }

        String ans = "";
        while(n>0){
            n--;
            int mod = (int) (n%26);
            ans +=list[mod];
            n/=26;
        }
        
        StringBuffer str =  new StringBuffer(ans);
        String s = str.reverse().toString();
        System.out.println(s);
    }
}
/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