import java.util.*;
public class Main {

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

        StringBuilder answer = new StringBuilder();
        while (n > 0) {
            n--;
            answer.append((char) ('a' + n % 26));
            n /= 26;
        }

        System.out.println(answer.reverse());
    }
} import java.util.*; util.* java public class Main {

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

        StringBuilder answer = new StringBuilder();
        while (n > 0) {
            n--;
            answer.append((char) ('a' + n % 26));
            n /= 26;
        }

        System.out.println(answer.reverse());
    }
} Main public static void main(String[] args)
    {
        Scanner in=new Scanner(System.in);
        long n = in.nextLong();

        StringBuilder answer = new StringBuilder();
        while (n > 0) {
            n--;
            answer.append((char) ('a' + n % 26));
            n /= 26;
        }

        System.out.println(answer.reverse());
    } main {
        Scanner in=new Scanner(System.in);
        long n = in.nextLong();

        StringBuilder answer = new StringBuilder();
        while (n > 0) {
            n--;
            answer.append((char) ('a' + n % 26));
            n /= 26;
        }

        System.out.println(answer.reverse());
    } Scanner in=new Scanner(System.in); in new Scanner(System.in) long n = in.nextLong(); n in.nextLong() in.nextLong in StringBuilder answer = new StringBuilder(); answer new StringBuilder() while (n > 0) {
            n--;
            answer.append((char) ('a' + n % 26));
            n /= 26;
        } n > 0 n 0 {
            n--;
            answer.append((char) ('a' + n % 26));
            n /= 26;
        } n-- n answer.append((char) ('a' + n % 26)) answer.append answer (char) ('a' + n % 26) 'a' n % 26 n 26 n /= 26 n 26 System.out.println(answer.reverse()) System.out.println System.out System System.out answer.reverse() answer.reverse answer String[] args args public class Main {

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

        StringBuilder answer = new StringBuilder();
        while (n > 0) {
            n--;
            answer.append((char) ('a' + n % 26));
            n /= 26;
        }

        System.out.println(answer.reverse());
    }
} public class Main {

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

        StringBuilder answer = new StringBuilder();
        while (n > 0) {
            n--;
            answer.append((char) ('a' + n % 26));
            n /= 26;
        }

        System.out.println(answer.reverse());
    }
} Main
import java.util.*;
public class Main {

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

        StringBuilder answer = new StringBuilder();
        while (n > 0) {
            n--;
            answer.append((char) ('a' + n % 26));
            n /= 26;
        }

        System.out.println(answer.reverse());
    }
}
