import java.util.*;
public class Main {
    static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) {
        long n = sc.nextLong();
        String res = "";
        while(n > 0){
            char c = (char)((n % 26 == 0 ? 26 : n % 26) - 1 + 'a');
            res = c + res;
            if(n % 26 == 0)
                n = n / 26 - 1;
            else
                n/= 26;
        }
        System.out.println(res);
    }
} import java.util.*; util.* java public class Main {
    static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) {
        long n = sc.nextLong();
        String res = "";
        while(n > 0){
            char c = (char)((n % 26 == 0 ? 26 : n % 26) - 1 + 'a');
            res = c + res;
            if(n % 26 == 0)
                n = n / 26 - 1;
            else
                n/= 26;
        }
        System.out.println(res);
    }
} Main static Scanner sc = new Scanner(System.in); sc new Scanner(System.in) public static void main(String[] args) {
        long n = sc.nextLong();
        String res = "";
        while(n > 0){
            char c = (char)((n % 26 == 0 ? 26 : n % 26) - 1 + 'a');
            res = c + res;
            if(n % 26 == 0)
                n = n / 26 - 1;
            else
                n/= 26;
        }
        System.out.println(res);
    } main {
        long n = sc.nextLong();
        String res = "";
        while(n > 0){
            char c = (char)((n % 26 == 0 ? 26 : n % 26) - 1 + 'a');
            res = c + res;
            if(n % 26 == 0)
                n = n / 26 - 1;
            else
                n/= 26;
        }
        System.out.println(res);
    } long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc String res = ""; res "" while(n > 0){
            char c = (char)((n % 26 == 0 ? 26 : n % 26) - 1 + 'a');
            res = c + res;
            if(n % 26 == 0)
                n = n / 26 - 1;
            else
                n/= 26;
        } n > 0 n 0 {
            char c = (char)((n % 26 == 0 ? 26 : n % 26) - 1 + 'a');
            res = c + res;
            if(n % 26 == 0)
                n = n / 26 - 1;
            else
                n/= 26;
        } char c = (char)((n % 26 == 0 ? 26 : n % 26) - 1 + 'a'); c (char)((n % 26 == 0 ? 26 : n % 26) - 1 + 'a') (n % 26 == 0 ? 26 : n % 26) - 1 (n % 26 == 0 ? 26 : n % 26) n % 26 == 0 n % 26 n 26 0 26 n % 26 n 26 1 'a' res = c + res res c + res c res if(n % 26 == 0)
                n = n / 26 - 1;
            else
                n/= 26; n % 26 == 0 n % 26 n 26 0 n = n / 26 - 1 n n / 26 - 1 n / 26 n 26 1 n/= 26 n 26 System.out.println(res) System.out.println System.out System System.out res String[] args args public class Main {
    static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) {
        long n = sc.nextLong();
        String res = "";
        while(n > 0){
            char c = (char)((n % 26 == 0 ? 26 : n % 26) - 1 + 'a');
            res = c + res;
            if(n % 26 == 0)
                n = n / 26 - 1;
            else
                n/= 26;
        }
        System.out.println(res);
    }
} public class Main {
    static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) {
        long n = sc.nextLong();
        String res = "";
        while(n > 0){
            char c = (char)((n % 26 == 0 ? 26 : n % 26) - 1 + 'a');
            res = c + res;
            if(n % 26 == 0)
                n = n / 26 - 1;
            else
                n/= 26;
        }
        System.out.println(res);
    }
} Main
import java.util.*;
public class Main {
    static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) {
        long n = sc.nextLong();
        String res = "";
        while(n > 0){
            char c = (char)((n % 26 == 0 ? 26 : n % 26) - 1 + 'a');
            res = c + res;
            if(n % 26 == 0)
                n = n / 26 - 1;
            else
                n/= 26;
        }
        System.out.println(res);
    }
}