import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        long n = Long.parseLong(sc.next());
        int k = 26;
        StringBuilder ans = new StringBuilder();
        while(n != 0) {
            char a = (char)(n % k + 96);
            if(n % k == 0) {
                a = 'z';
                ans.insert(0, a); 
                n /= k;
                n--;
            }else {
                ans.insert(0, a);  
                n /= k;
            }
        }
        System.out.println(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