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