import java.util.*;
public class Main {
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		String ans="";
		char c[]=new char[12];
		int q=0;
		
		while(n>0) {
			n--;
			c[q++]=(char)(n%26+'a');
			n/=26;
		}
		
		for(int i=q-1;i>=0;i--) {
			System.out.print(c[i]);
		}
		System.out.println();
	}
	
	

}
/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