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());


		String ans = "";
		while(n != 0) {
			char tmp;
			if(n%26 == 0) {
				tmp = 'z';
				n = n/26 -1;
			}else {
				tmp = (char) (n%26 +96);
				n /= 26;

			}

			ans = tmp + ans;

		}
		System.out.println(ans);
	}
}

 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());


		String ans = "";
		while(n != 0) {
			char tmp;
			if(n%26 == 0) {
				tmp = 'z';
				n = n/26 -1;
			}else {
				tmp = (char) (n%26 +96);
				n /= 26;

			}

			ans = tmp + ans;

		}
		System.out.println(ans);
	}
} Main public static void main(String[] args)  {
		Scanner sc = new Scanner(System.in);
		Long n = Long.parseLong(sc.next());


		String ans = "";
		while(n != 0) {
			char tmp;
			if(n%26 == 0) {
				tmp = 'z';
				n = n/26 -1;
			}else {
				tmp = (char) (n%26 +96);
				n /= 26;

			}

			ans = tmp + ans;

		}
		System.out.println(ans);
	} main {
		Scanner sc = new Scanner(System.in);
		Long n = Long.parseLong(sc.next());


		String ans = "";
		while(n != 0) {
			char tmp;
			if(n%26 == 0) {
				tmp = 'z';
				n = n/26 -1;
			}else {
				tmp = (char) (n%26 +96);
				n /= 26;

			}

			ans = tmp + ans;

		}
		System.out.println(ans);
	} 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 String ans = ""; ans "" while(n != 0) {
			char tmp;
			if(n%26 == 0) {
				tmp = 'z';
				n = n/26 -1;
			}else {
				tmp = (char) (n%26 +96);
				n /= 26;

			}

			ans = tmp + ans;

		} n != 0 n 0 {
			char tmp;
			if(n%26 == 0) {
				tmp = 'z';
				n = n/26 -1;
			}else {
				tmp = (char) (n%26 +96);
				n /= 26;

			}

			ans = tmp + ans;

		} char tmp; tmp if(n%26 == 0) {
				tmp = 'z';
				n = n/26 -1;
			}else {
				tmp = (char) (n%26 +96);
				n /= 26;

			} n%26 == 0 n%26 n 26 0 {
				tmp = 'z';
				n = n/26 -1;
			} tmp = 'z' tmp 'z' n = n/26 -1 n n/26 -1 n/26 n 26 1 {
				tmp = (char) (n%26 +96);
				n /= 26;

			} tmp = (char) (n%26 +96) tmp (char) (n%26 +96) n%26 n 26 96 n /= 26 n 26 ans = tmp + ans ans tmp + ans tmp ans System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {

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


		String ans = "";
		while(n != 0) {
			char tmp;
			if(n%26 == 0) {
				tmp = 'z';
				n = n/26 -1;
			}else {
				tmp = (char) (n%26 +96);
				n /= 26;

			}

			ans = tmp + ans;

		}
		System.out.println(ans);
	}
} public class Main {

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


		String ans = "";
		while(n != 0) {
			char tmp;
			if(n%26 == 0) {
				tmp = 'z';
				n = n/26 -1;
			}else {
				tmp = (char) (n%26 +96);
				n /= 26;

			}

			ans = tmp + ans;

		}
		System.out.println(ans);
	}
} 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());


		String ans = "";
		while(n != 0) {
			char tmp;
			if(n%26 == 0) {
				tmp = 'z';
				n = n/26 -1;
			}else {
				tmp = (char) (n%26 +96);
				n /= 26;

			}

			ans = tmp + ans;

		}
		System.out.println(ans);
	}
}


