import java.util.Scanner;

public class Main {

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

		long n = Long.parseLong(sc.next());

		int c = 'a';

		StringBuilder sb = new StringBuilder();
		while (n != 0) {
			long remainder = (n - 1) % 26;
			sb.append((char) (c + remainder));

			n = (n - remainder + 1) / 26;
		}

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

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

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

		long n = Long.parseLong(sc.next());

		int c = 'a';

		StringBuilder sb = new StringBuilder();
		while (n != 0) {
			long remainder = (n - 1) % 26;
			sb.append((char) (c + remainder));

			n = (n - remainder + 1) / 26;
		}

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

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

		long n = Long.parseLong(sc.next());

		int c = 'a';

		StringBuilder sb = new StringBuilder();
		while (n != 0) {
			long remainder = (n - 1) % 26;
			sb.append((char) (c + remainder));

			n = (n - remainder + 1) / 26;
		}

		System.out.println(sb.reverse());
	} main {
		Scanner sc = new Scanner(System.in);

		long n = Long.parseLong(sc.next());

		int c = 'a';

		StringBuilder sb = new StringBuilder();
		while (n != 0) {
			long remainder = (n - 1) % 26;
			sb.append((char) (c + remainder));

			n = (n - remainder + 1) / 26;
		}

		System.out.println(sb.reverse());
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = Long.parseLong(sc.next()); n Long.parseLong(sc.next()) Long.parseLong Long sc.next() sc.next sc int c = 'a'; c 'a' StringBuilder sb = new StringBuilder(); sb new StringBuilder() while (n != 0) {
			long remainder = (n - 1) % 26;
			sb.append((char) (c + remainder));

			n = (n - remainder + 1) / 26;
		} n != 0 n 0 {
			long remainder = (n - 1) % 26;
			sb.append((char) (c + remainder));

			n = (n - remainder + 1) / 26;
		} long remainder = (n - 1) % 26; remainder (n - 1) % 26 (n - 1) n 1 26 sb.append((char) (c + remainder)) sb.append sb (char) (c + remainder) c remainder n = (n - remainder + 1) / 26 n (n - remainder + 1) / 26 (n - remainder + 1) n - remainder n remainder 1 26 System.out.println(sb.reverse()) System.out.println System.out System System.out sb.reverse() sb.reverse sb String[] args args public class Main {

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

		long n = Long.parseLong(sc.next());

		int c = 'a';

		StringBuilder sb = new StringBuilder();
		while (n != 0) {
			long remainder = (n - 1) % 26;
			sb.append((char) (c + remainder));

			n = (n - remainder + 1) / 26;
		}

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

} public class Main {

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

		long n = Long.parseLong(sc.next());

		int c = 'a';

		StringBuilder sb = new StringBuilder();
		while (n != 0) {
			long remainder = (n - 1) % 26;
			sb.append((char) (c + remainder));

			n = (n - remainder + 1) / 26;
		}

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

} Main
import java.util.Scanner;

public class Main {

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

		long n = Long.parseLong(sc.next());

		int c = 'a';

		StringBuilder sb = new StringBuilder();
		while (n != 0) {
			long remainder = (n - 1) % 26;
			sb.append((char) (c + remainder));

			n = (n - remainder + 1) / 26;
		}

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

}
