import java.util.Scanner;

public class Main {

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

		while (N > 0) {
			N--;
			answer = (char) ('a' + (N % 26)) + answer;
			N = N / 26;
		}

		System.out.println(answer);
	}

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

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

		while (N > 0) {
			N--;
			answer = (char) ('a' + (N % 26)) + answer;
			N = N / 26;
		}

		System.out.println(answer);
	}

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

		while (N > 0) {
			N--;
			answer = (char) ('a' + (N % 26)) + answer;
			N = N / 26;
		}

		System.out.println(answer);
	} main {
		Scanner scan = new Scanner(System.in);
		long N = scan.nextLong();
		String answer = "";

		while (N > 0) {
			N--;
			answer = (char) ('a' + (N % 26)) + answer;
			N = N / 26;
		}

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

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

		while (N > 0) {
			N--;
			answer = (char) ('a' + (N % 26)) + answer;
			N = N / 26;
		}

		System.out.println(answer);
	}

} public class Main {

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

		while (N > 0) {
			N--;
			answer = (char) ('a' + (N % 26)) + answer;
			N = N / 26;
		}

		System.out.println(answer);
	}

} Main
import java.util.Scanner;

public class Main {

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

		while (N > 0) {
			N--;
			answer = (char) ('a' + (N % 26)) + answer;
			N = N / 26;
		}

		System.out.println(answer);
	}

}