import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		char[] alphabet = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
//		n -= 1;
		String s = "";
		do {
			n -= 1;
			int z = (int)((n)%26);
			s = alphabet[z] + s;
			n /= 26;
		}while(n>0);
		System.out.println(s);
	}

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

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		char[] alphabet = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
//		n -= 1;
		String s = "";
		do {
			n -= 1;
			int z = (int)((n)%26);
			s = alphabet[z] + s;
			n /= 26;
		}while(n>0);
		System.out.println(s);
	}

} Main public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		char[] alphabet = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
//		n -= 1;
		String s = "";
		do {
			n -= 1;
			int z = (int)((n)%26);
			s = alphabet[z] + s;
			n /= 26;
		}while(n>0);
		System.out.println(s);
	} main {
		// TODO 自動生成されたメソッド・スタブ
		char[] alphabet = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
//		n -= 1;
		String s = "";
		do {
			n -= 1;
			int z = (int)((n)%26);
			s = alphabet[z] + s;
			n /= 26;
		}while(n>0);
		System.out.println(s);
	} char[] alphabet = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'}; alphabet {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'} 'a' 'b' 'c' 'd' 'e' 'f' 'g' 'h' 'i' 'j' 'k' 'l' 'm' 'n' 'o' 'p' 'q' 'r' 's' 't' 'u' 'v' 'w' 'x' 'y' 'z' Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc String s = ""; s "" do {
			n -= 1;
			int z = (int)((n)%26);
			s = alphabet[z] + s;
			n /= 26;
		}while(n>0); n>0 n 0 {
			n -= 1;
			int z = (int)((n)%26);
			s = alphabet[z] + s;
			n /= 26;
		} n -= 1 n 1 int z = (int)((n)%26); z (int)((n)%26) (n) 26 s = alphabet[z] + s s alphabet[z] + s alphabet[z] alphabet z s n /= 26 n 26 System.out.println(s) System.out.println System.out System System.out s String[] args args public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		char[] alphabet = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
//		n -= 1;
		String s = "";
		do {
			n -= 1;
			int z = (int)((n)%26);
			s = alphabet[z] + s;
			n /= 26;
		}while(n>0);
		System.out.println(s);
	}

} public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		char[] alphabet = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
//		n -= 1;
		String s = "";
		do {
			n -= 1;
			int z = (int)((n)%26);
			s = alphabet[z] + s;
			n /= 26;
		}while(n>0);
		System.out.println(s);
	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		char[] alphabet = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
//		n -= 1;
		String s = "";
		do {
			n -= 1;
			int z = (int)((n)%26);
			s = alphabet[z] + s;
			n /= 26;
		}while(n>0);
		System.out.println(s);
	}

}
