import java.util.*;

public class Main {
    public static void main(String args[]) {
        Scanner scn = new Scanner(System.in);
        long n = scn.nextLong();
        String s = "abcdefghijklmnopqrstuvwxyz";
        String ans = "";
        n = n - 1;
        int a;
        char c;


        while (n / 26!=0) {
            long num = n % 26;
            a = (int) num;
            c = s.charAt(a);
            ans = String.valueOf(c) + ans;

            n = (n / 26)-1;

        }
        long num = n % 26;
        a = (int) num;
        c = s.charAt(a);
        ans = String.valueOf(c) + ans;



        System.out.println(ans);

        scn.close();

    }


} import java.util.*; util.* java public class Main {
    public static void main(String args[]) {
        Scanner scn = new Scanner(System.in);
        long n = scn.nextLong();
        String s = "abcdefghijklmnopqrstuvwxyz";
        String ans = "";
        n = n - 1;
        int a;
        char c;


        while (n / 26!=0) {
            long num = n % 26;
            a = (int) num;
            c = s.charAt(a);
            ans = String.valueOf(c) + ans;

            n = (n / 26)-1;

        }
        long num = n % 26;
        a = (int) num;
        c = s.charAt(a);
        ans = String.valueOf(c) + ans;



        System.out.println(ans);

        scn.close();

    }


} Main public static void main(String args[]) {
        Scanner scn = new Scanner(System.in);
        long n = scn.nextLong();
        String s = "abcdefghijklmnopqrstuvwxyz";
        String ans = "";
        n = n - 1;
        int a;
        char c;


        while (n / 26!=0) {
            long num = n % 26;
            a = (int) num;
            c = s.charAt(a);
            ans = String.valueOf(c) + ans;

            n = (n / 26)-1;

        }
        long num = n % 26;
        a = (int) num;
        c = s.charAt(a);
        ans = String.valueOf(c) + ans;



        System.out.println(ans);

        scn.close();

    } main {
        Scanner scn = new Scanner(System.in);
        long n = scn.nextLong();
        String s = "abcdefghijklmnopqrstuvwxyz";
        String ans = "";
        n = n - 1;
        int a;
        char c;


        while (n / 26!=0) {
            long num = n % 26;
            a = (int) num;
            c = s.charAt(a);
            ans = String.valueOf(c) + ans;

            n = (n / 26)-1;

        }
        long num = n % 26;
        a = (int) num;
        c = s.charAt(a);
        ans = String.valueOf(c) + ans;



        System.out.println(ans);

        scn.close();

    } Scanner scn = new Scanner(System.in); scn new Scanner(System.in) long n = scn.nextLong(); n scn.nextLong() scn.nextLong scn String s = "abcdefghijklmnopqrstuvwxyz"; s "abcdefghijklmnopqrstuvwxyz" String ans = ""; ans "" n = n - 1 n n - 1 n 1 int a; a char c; c while (n / 26!=0) {
            long num = n % 26;
            a = (int) num;
            c = s.charAt(a);
            ans = String.valueOf(c) + ans;

            n = (n / 26)-1;

        } n / 26!=0 n / 26 n 26 0 {
            long num = n % 26;
            a = (int) num;
            c = s.charAt(a);
            ans = String.valueOf(c) + ans;

            n = (n / 26)-1;

        } long num = n % 26; num n % 26 n 26 a = (int) num a (int) num c = s.charAt(a) c s.charAt(a) s.charAt s a ans = String.valueOf(c) + ans ans String.valueOf(c) + ans String.valueOf(c) String.valueOf String c ans n = (n / 26)-1 n (n / 26)-1 (n / 26) n 26 1 long num = n % 26; num n % 26 n 26 a = (int) num a (int) num c = s.charAt(a) c s.charAt(a) s.charAt s a ans = String.valueOf(c) + ans ans String.valueOf(c) + ans String.valueOf(c) String.valueOf String c ans System.out.println(ans) System.out.println System.out System System.out ans scn.close() scn.close scn String args[] args public class Main {
    public static void main(String args[]) {
        Scanner scn = new Scanner(System.in);
        long n = scn.nextLong();
        String s = "abcdefghijklmnopqrstuvwxyz";
        String ans = "";
        n = n - 1;
        int a;
        char c;


        while (n / 26!=0) {
            long num = n % 26;
            a = (int) num;
            c = s.charAt(a);
            ans = String.valueOf(c) + ans;

            n = (n / 26)-1;

        }
        long num = n % 26;
        a = (int) num;
        c = s.charAt(a);
        ans = String.valueOf(c) + ans;



        System.out.println(ans);

        scn.close();

    }


} public class Main {
    public static void main(String args[]) {
        Scanner scn = new Scanner(System.in);
        long n = scn.nextLong();
        String s = "abcdefghijklmnopqrstuvwxyz";
        String ans = "";
        n = n - 1;
        int a;
        char c;


        while (n / 26!=0) {
            long num = n % 26;
            a = (int) num;
            c = s.charAt(a);
            ans = String.valueOf(c) + ans;

            n = (n / 26)-1;

        }
        long num = n % 26;
        a = (int) num;
        c = s.charAt(a);
        ans = String.valueOf(c) + ans;



        System.out.println(ans);

        scn.close();

    }


} Main
import java.util.*;

public class Main {
    public static void main(String args[]) {
        Scanner scn = new Scanner(System.in);
        long n = scn.nextLong();
        String s = "abcdefghijklmnopqrstuvwxyz";
        String ans = "";
        n = n - 1;
        int a;
        char c;


        while (n / 26!=0) {
            long num = n % 26;
            a = (int) num;
            c = s.charAt(a);
            ans = String.valueOf(c) + ans;

            n = (n / 26)-1;

        }
        long num = n % 26;
        a = (int) num;
        c = s.charAt(a);
        ans = String.valueOf(c) + ans;



        System.out.println(ans);

        scn.close();

    }


}
