import java.util.*;

public class Main {

    static int gcd (int a, int b) {return b>0?gcd(b,a%b):a;}

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();
        String ans = "";
        String s = "zabcdefghijklmnopqrstuvwxy";
        char[] c = s.toCharArray();


        while(true){
            long mod = N % s.length();
            ans =  c[(int)mod] + ans;

            if( ( (N -1) / s.length()) < 1){
                break;
            } else{
                N = ((N-1) / s.length());
            }

        }

        System.out.println(ans);

    }

} import java.util.*; util.* java public class Main {

    static int gcd (int a, int b) {return b>0?gcd(b,a%b):a;}

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();
        String ans = "";
        String s = "zabcdefghijklmnopqrstuvwxy";
        char[] c = s.toCharArray();


        while(true){
            long mod = N % s.length();
            ans =  c[(int)mod] + ans;

            if( ( (N -1) / s.length()) < 1){
                break;
            } else{
                N = ((N-1) / s.length());
            }

        }

        System.out.println(ans);

    }

} Main static int gcd (int a, int b) {return b>0?gcd(b,a%b):a;} gcd {return b>0?gcd(b,a%b):a;} return b>0?gcd(b,a%b):a; b>0?gcd(b,a%b):a b>0 b 0 gcd(b,a%b) gcd b a%b a b a int a a int b b public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();
        String ans = "";
        String s = "zabcdefghijklmnopqrstuvwxy";
        char[] c = s.toCharArray();


        while(true){
            long mod = N % s.length();
            ans =  c[(int)mod] + ans;

            if( ( (N -1) / s.length()) < 1){
                break;
            } else{
                N = ((N-1) / s.length());
            }

        }

        System.out.println(ans);

    } main {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();
        String ans = "";
        String s = "zabcdefghijklmnopqrstuvwxy";
        char[] c = s.toCharArray();


        while(true){
            long mod = N % s.length();
            ans =  c[(int)mod] + ans;

            if( ( (N -1) / s.length()) < 1){
                break;
            } else{
                N = ((N-1) / s.length());
            }

        }

        System.out.println(ans);

    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long N = sc.nextLong(); N sc.nextLong() sc.nextLong sc String ans = ""; ans "" String s = "zabcdefghijklmnopqrstuvwxy"; s "zabcdefghijklmnopqrstuvwxy" char[] c = s.toCharArray(); c s.toCharArray() s.toCharArray s while(true){
            long mod = N % s.length();
            ans =  c[(int)mod] + ans;

            if( ( (N -1) / s.length()) < 1){
                break;
            } else{
                N = ((N-1) / s.length());
            }

        } true {
            long mod = N % s.length();
            ans =  c[(int)mod] + ans;

            if( ( (N -1) / s.length()) < 1){
                break;
            } else{
                N = ((N-1) / s.length());
            }

        } long mod = N % s.length(); mod N % s.length() N s.length() s.length s ans =  c[(int)mod] + ans ans c[(int)mod] + ans c[(int)mod] c (int)mod ans if( ( (N -1) / s.length()) < 1){
                break;
            } else{
                N = ((N-1) / s.length());
            } ( (N -1) / s.length()) < 1 ( (N -1) / s.length()) (N -1) N 1 s.length() s.length s 1 {
                break;
            } break; {
                N = ((N-1) / s.length());
            } N = ((N-1) / s.length()) N ((N-1) / s.length()) (N-1) N 1 s.length() s.length s System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {

    static int gcd (int a, int b) {return b>0?gcd(b,a%b):a;}

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();
        String ans = "";
        String s = "zabcdefghijklmnopqrstuvwxy";
        char[] c = s.toCharArray();


        while(true){
            long mod = N % s.length();
            ans =  c[(int)mod] + ans;

            if( ( (N -1) / s.length()) < 1){
                break;
            } else{
                N = ((N-1) / s.length());
            }

        }

        System.out.println(ans);

    }

} public class Main {

    static int gcd (int a, int b) {return b>0?gcd(b,a%b):a;}

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();
        String ans = "";
        String s = "zabcdefghijklmnopqrstuvwxy";
        char[] c = s.toCharArray();


        while(true){
            long mod = N % s.length();
            ans =  c[(int)mod] + ans;

            if( ( (N -1) / s.length()) < 1){
                break;
            } else{
                N = ((N-1) / s.length());
            }

        }

        System.out.println(ans);

    }

} Main
import java.util.*;

public class Main {

    static int gcd (int a, int b) {return b>0?gcd(b,a%b):a;}

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();
        String ans = "";
        String s = "zabcdefghijklmnopqrstuvwxy";
        char[] c = s.toCharArray();


        while(true){
            long mod = N % s.length();
            ans =  c[(int)mod] + ans;

            if( ( (N -1) / s.length()) < 1){
                break;
            } else{
                N = ((N-1) / s.length());
            }

        }

        System.out.println(ans);

    }

}
