import java.util.*;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		Long n = sc.nextLong();
		StringBuilder sb = new StringBuilder();
		while (n > 0) {
			n--;
			sb.insert(0, (char) ('a' + n % 26));
			n = n / 26;
		}
		System.out.println(sb.toString());
	}
}





 import java.util.*; util.* java public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		Long n = sc.nextLong();
		StringBuilder sb = new StringBuilder();
		while (n > 0) {
			n--;
			sb.insert(0, (char) ('a' + n % 26));
			n = n / 26;
		}
		System.out.println(sb.toString());
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		Long n = sc.nextLong();
		StringBuilder sb = new StringBuilder();
		while (n > 0) {
			n--;
			sb.insert(0, (char) ('a' + n % 26));
			n = n / 26;
		}
		System.out.println(sb.toString());
	} main {
		Scanner sc = new Scanner(System.in);
		Long n = sc.nextLong();
		StringBuilder sb = new StringBuilder();
		while (n > 0) {
			n--;
			sb.insert(0, (char) ('a' + n % 26));
			n = n / 26;
		}
		System.out.println(sb.toString());
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) Long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc StringBuilder sb = new StringBuilder(); sb new StringBuilder() while (n > 0) {
			n--;
			sb.insert(0, (char) ('a' + n % 26));
			n = n / 26;
		} n > 0 n 0 {
			n--;
			sb.insert(0, (char) ('a' + n % 26));
			n = n / 26;
		} n-- n sb.insert(0, (char) ('a' + n % 26)) sb.insert sb 0 (char) ('a' + n % 26) 'a' n % 26 n 26 n = n / 26 n n / 26 n 26 System.out.println(sb.toString()) System.out.println System.out System System.out sb.toString() sb.toString sb String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		Long n = sc.nextLong();
		StringBuilder sb = new StringBuilder();
		while (n > 0) {
			n--;
			sb.insert(0, (char) ('a' + n % 26));
			n = n / 26;
		}
		System.out.println(sb.toString());
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		Long n = sc.nextLong();
		StringBuilder sb = new StringBuilder();
		while (n > 0) {
			n--;
			sb.insert(0, (char) ('a' + n % 26));
			n = n / 26;
		}
		System.out.println(sb.toString());
	}
} Main
import java.util.*;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		Long n = sc.nextLong();
		StringBuilder sb = new StringBuilder();
		while (n > 0) {
			n--;
			sb.insert(0, (char) ('a' + n % 26));
			n = n / 26;
		}
		System.out.println(sb.toString());
	}
}






