import java.util.Scanner;

public class Main {

	/** 英文字のアルファベット */
	private static final char[] ALPHABET = "abcdefghijklmnopqrstuvwxyz".toCharArray();

	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			long n = scanner.nextLong();
			StringBuilder sb = new StringBuilder();
			while (n > 0) {
				sb.append(ALPHABET[(int) ((n - 1) % 26)]);
				n = (n - 1) / 26;
			}
			System.out.println(sb.reverse().toString());
		}
	}
} import java.util.Scanner; Scanner java.util public class Main {

	/** 英文字のアルファベット */
	private static final char[] ALPHABET = "abcdefghijklmnopqrstuvwxyz".toCharArray();

	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			long n = scanner.nextLong();
			StringBuilder sb = new StringBuilder();
			while (n > 0) {
				sb.append(ALPHABET[(int) ((n - 1) % 26)]);
				n = (n - 1) / 26;
			}
			System.out.println(sb.reverse().toString());
		}
	}
} Main /** 英文字のアルファベット */
	private static final char[] ALPHABET = "abcdefghijklmnopqrstuvwxyz".toCharArray(); ALPHABET "abcdefghijklmnopqrstuvwxyz".toCharArray() "abcdefghijklmnopqrstuvwxyz".toCharArray "abcdefghijklmnopqrstuvwxyz" public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			long n = scanner.nextLong();
			StringBuilder sb = new StringBuilder();
			while (n > 0) {
				sb.append(ALPHABET[(int) ((n - 1) % 26)]);
				n = (n - 1) / 26;
			}
			System.out.println(sb.reverse().toString());
		}
	} main {
		try (Scanner scanner = new Scanner(System.in)) {
			long n = scanner.nextLong();
			StringBuilder sb = new StringBuilder();
			while (n > 0) {
				sb.append(ALPHABET[(int) ((n - 1) % 26)]);
				n = (n - 1) / 26;
			}
			System.out.println(sb.reverse().toString());
		}
	} try (Scanner scanner = new Scanner(System.in)) {
			long n = scanner.nextLong();
			StringBuilder sb = new StringBuilder();
			while (n > 0) {
				sb.append(ALPHABET[(int) ((n - 1) % 26)]);
				n = (n - 1) / 26;
			}
			System.out.println(sb.reverse().toString());
		} {
			long n = scanner.nextLong();
			StringBuilder sb = new StringBuilder();
			while (n > 0) {
				sb.append(ALPHABET[(int) ((n - 1) % 26)]);
				n = (n - 1) / 26;
			}
			System.out.println(sb.reverse().toString());
		} Scanner scanner = new Scanner(System.in) Scanner scanner = new Scanner(System.in) new Scanner(System.in) long n = scanner.nextLong(); n scanner.nextLong() scanner.nextLong scanner StringBuilder sb = new StringBuilder(); sb new StringBuilder() while (n > 0) {
				sb.append(ALPHABET[(int) ((n - 1) % 26)]);
				n = (n - 1) / 26;
			} n > 0 n 0 {
				sb.append(ALPHABET[(int) ((n - 1) % 26)]);
				n = (n - 1) / 26;
			} sb.append(ALPHABET[(int) ((n - 1) % 26)]) sb.append sb ALPHABET[(int) ((n - 1) % 26)] ALPHABET (int) ((n - 1) % 26) (n - 1) n 1 26 n = (n - 1) / 26 n (n - 1) / 26 (n - 1) n 1 26 System.out.println(sb.reverse().toString()) System.out.println System.out System System.out sb.reverse().toString() sb.reverse().toString sb.reverse() sb.reverse sb String[] args args public class Main {

	/** 英文字のアルファベット */
	private static final char[] ALPHABET = "abcdefghijklmnopqrstuvwxyz".toCharArray();

	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			long n = scanner.nextLong();
			StringBuilder sb = new StringBuilder();
			while (n > 0) {
				sb.append(ALPHABET[(int) ((n - 1) % 26)]);
				n = (n - 1) / 26;
			}
			System.out.println(sb.reverse().toString());
		}
	}
} public class Main {

	/** 英文字のアルファベット */
	private static final char[] ALPHABET = "abcdefghijklmnopqrstuvwxyz".toCharArray();

	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			long n = scanner.nextLong();
			StringBuilder sb = new StringBuilder();
			while (n > 0) {
				sb.append(ALPHABET[(int) ((n - 1) % 26)]);
				n = (n - 1) / 26;
			}
			System.out.println(sb.reverse().toString());
		}
	}
} Main
import java.util.Scanner;

public class Main {

	/** 英文字のアルファベット */
	private static final char[] ALPHABET = "abcdefghijklmnopqrstuvwxyz".toCharArray();

	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			long n = scanner.nextLong();
			StringBuilder sb = new StringBuilder();
			while (n > 0) {
				sb.append(ALPHABET[(int) ((n - 1) % 26)]);
				n = (n - 1) / 26;
			}
			System.out.println(sb.reverse().toString());
		}
	}
}
