import java.util.Scanner;

public class Main {

    public Main() {
        Scanner scanner = new Scanner(System.in);
        long N = scanner.nextLong();

        String R = "";
        while(N > 0){
            char C = (char)(N%26L);
            if(C == 0) C = 26;
            N = (N - C) / 26L;
            C = (char)('a'+C-1);
            R = C + R;
        }

        System.out.println(R);
    }

    public static void main(String[] args) {
        new Main();
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public Main() {
        Scanner scanner = new Scanner(System.in);
        long N = scanner.nextLong();

        String R = "";
        while(N > 0){
            char C = (char)(N%26L);
            if(C == 0) C = 26;
            N = (N - C) / 26L;
            C = (char)('a'+C-1);
            R = C + R;
        }

        System.out.println(R);
    }

    public static void main(String[] args) {
        new Main();
    }
} Main public Main() {
        Scanner scanner = new Scanner(System.in);
        long N = scanner.nextLong();

        String R = "";
        while(N > 0){
            char C = (char)(N%26L);
            if(C == 0) C = 26;
            N = (N - C) / 26L;
            C = (char)('a'+C-1);
            R = C + R;
        }

        System.out.println(R);
    } Main {
        Scanner scanner = new Scanner(System.in);
        long N = scanner.nextLong();

        String R = "";
        while(N > 0){
            char C = (char)(N%26L);
            if(C == 0) C = 26;
            N = (N - C) / 26L;
            C = (char)('a'+C-1);
            R = C + R;
        }

        System.out.println(R);
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) long N = scanner.nextLong(); N scanner.nextLong() scanner.nextLong scanner String R = ""; R "" while(N > 0){
            char C = (char)(N%26L);
            if(C == 0) C = 26;
            N = (N - C) / 26L;
            C = (char)('a'+C-1);
            R = C + R;
        } N > 0 N 0 {
            char C = (char)(N%26L);
            if(C == 0) C = 26;
            N = (N - C) / 26L;
            C = (char)('a'+C-1);
            R = C + R;
        } char C = (char)(N%26L); C (char)(N%26L) N 26L if(C == 0) C = 26; C == 0 C 0 C = 26 C 26 N = (N - C) / 26L N (N - C) / 26L (N - C) N C 26L C = (char)('a'+C-1) C (char)('a'+C-1) 'a'+C 'a' C 1 R = C + R R C + R C R System.out.println(R) System.out.println System.out System System.out R public static void main(String[] args) {
        new Main();
    } main {
        new Main();
    } new Main() String[] args args public class Main {

    public Main() {
        Scanner scanner = new Scanner(System.in);
        long N = scanner.nextLong();

        String R = "";
        while(N > 0){
            char C = (char)(N%26L);
            if(C == 0) C = 26;
            N = (N - C) / 26L;
            C = (char)('a'+C-1);
            R = C + R;
        }

        System.out.println(R);
    }

    public static void main(String[] args) {
        new Main();
    }
} public class Main {

    public Main() {
        Scanner scanner = new Scanner(System.in);
        long N = scanner.nextLong();

        String R = "";
        while(N > 0){
            char C = (char)(N%26L);
            if(C == 0) C = 26;
            N = (N - C) / 26L;
            C = (char)('a'+C-1);
            R = C + R;
        }

        System.out.println(R);
    }

    public static void main(String[] args) {
        new Main();
    }
} Main
import java.util.Scanner;

public class Main {

    public Main() {
        Scanner scanner = new Scanner(System.in);
        long N = scanner.nextLong();

        String R = "";
        while(N > 0){
            char C = (char)(N%26L);
            if(C == 0) C = 26;
            N = (N - C) / 26L;
            C = (char)('a'+C-1);
            R = C + R;
        }

        System.out.println(R);
    }

    public static void main(String[] args) {
        new Main();
    }
}
