import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in)) {
			long num = sc.nextLong() - 1;
			String name = "";

			while (num >= 0) {
				int mod = (int) (num % 26);
				name = ((char) ('a' + mod) + name);
				num = num / 26 - 1;
			}
			System.out.println(name);
		}
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in)) {
			long num = sc.nextLong() - 1;
			String name = "";

			while (num >= 0) {
				int mod = (int) (num % 26);
				name = ((char) ('a' + mod) + name);
				num = num / 26 - 1;
			}
			System.out.println(name);
		}
	}
} Main public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in)) {
			long num = sc.nextLong() - 1;
			String name = "";

			while (num >= 0) {
				int mod = (int) (num % 26);
				name = ((char) ('a' + mod) + name);
				num = num / 26 - 1;
			}
			System.out.println(name);
		}
	} main {
		try (Scanner sc = new Scanner(System.in)) {
			long num = sc.nextLong() - 1;
			String name = "";

			while (num >= 0) {
				int mod = (int) (num % 26);
				name = ((char) ('a' + mod) + name);
				num = num / 26 - 1;
			}
			System.out.println(name);
		}
	} try (Scanner sc = new Scanner(System.in)) {
			long num = sc.nextLong() - 1;
			String name = "";

			while (num >= 0) {
				int mod = (int) (num % 26);
				name = ((char) ('a' + mod) + name);
				num = num / 26 - 1;
			}
			System.out.println(name);
		} {
			long num = sc.nextLong() - 1;
			String name = "";

			while (num >= 0) {
				int mod = (int) (num % 26);
				name = ((char) ('a' + mod) + name);
				num = num / 26 - 1;
			}
			System.out.println(name);
		} Scanner sc = new Scanner(System.in) Scanner sc = new Scanner(System.in) new Scanner(System.in) long num = sc.nextLong() - 1; num sc.nextLong() - 1 sc.nextLong() sc.nextLong sc 1 String name = ""; name "" while (num >= 0) {
				int mod = (int) (num % 26);
				name = ((char) ('a' + mod) + name);
				num = num / 26 - 1;
			} num >= 0 num 0 {
				int mod = (int) (num % 26);
				name = ((char) ('a' + mod) + name);
				num = num / 26 - 1;
			} int mod = (int) (num % 26); mod (int) (num % 26) num 26 name = ((char) ('a' + mod) + name) name ((char) ('a' + mod) + name) (char) ('a' + mod) 'a' mod name num = num / 26 - 1 num num / 26 - 1 num / 26 num 26 1 System.out.println(name) System.out.println System.out System System.out name String[] args args public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in)) {
			long num = sc.nextLong() - 1;
			String name = "";

			while (num >= 0) {
				int mod = (int) (num % 26);
				name = ((char) ('a' + mod) + name);
				num = num / 26 - 1;
			}
			System.out.println(name);
		}
	}
} public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in)) {
			long num = sc.nextLong() - 1;
			String name = "";

			while (num >= 0) {
				int mod = (int) (num % 26);
				name = ((char) ('a' + mod) + name);
				num = num / 26 - 1;
			}
			System.out.println(name);
		}
	}
} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in)) {
			long num = sc.nextLong() - 1;
			String name = "";

			while (num >= 0) {
				int mod = (int) (num % 26);
				name = ((char) ('a' + mod) + name);
				num = num / 26 - 1;
			}
			System.out.println(name);
		}
	}
}
