import java.util.*;

public class Main {
public static void main(String[] args) {
		
		Scanner keyboard = new Scanner(System.in); 
		
		long N  = keyboard.nextLong();
		
		String S = "abcdefghijklmnopqrstuvwxyz";
		String[] s = S.split("");
		
		StringBuffer ans = new StringBuffer("");
		
		while(N > 0) {
			int j = (int)((N-1)%26);
			N = (N-1)/26;
			ans.append(s[j]);
		}
		
		System.out.print(ans.reverse());
		keyboard.close();	
	}
} import java.util.*; util.* java public class Main {
public static void main(String[] args) {
		
		Scanner keyboard = new Scanner(System.in); 
		
		long N  = keyboard.nextLong();
		
		String S = "abcdefghijklmnopqrstuvwxyz";
		String[] s = S.split("");
		
		StringBuffer ans = new StringBuffer("");
		
		while(N > 0) {
			int j = (int)((N-1)%26);
			N = (N-1)/26;
			ans.append(s[j]);
		}
		
		System.out.print(ans.reverse());
		keyboard.close();	
	}
} Main public static void main(String[] args) {
		
		Scanner keyboard = new Scanner(System.in); 
		
		long N  = keyboard.nextLong();
		
		String S = "abcdefghijklmnopqrstuvwxyz";
		String[] s = S.split("");
		
		StringBuffer ans = new StringBuffer("");
		
		while(N > 0) {
			int j = (int)((N-1)%26);
			N = (N-1)/26;
			ans.append(s[j]);
		}
		
		System.out.print(ans.reverse());
		keyboard.close();	
	} main {
		
		Scanner keyboard = new Scanner(System.in); 
		
		long N  = keyboard.nextLong();
		
		String S = "abcdefghijklmnopqrstuvwxyz";
		String[] s = S.split("");
		
		StringBuffer ans = new StringBuffer("");
		
		while(N > 0) {
			int j = (int)((N-1)%26);
			N = (N-1)/26;
			ans.append(s[j]);
		}
		
		System.out.print(ans.reverse());
		keyboard.close();	
	} Scanner keyboard = new Scanner(System.in); keyboard new Scanner(System.in) long N  = keyboard.nextLong(); N keyboard.nextLong() keyboard.nextLong keyboard String S = "abcdefghijklmnopqrstuvwxyz"; S "abcdefghijklmnopqrstuvwxyz" String[] s = S.split(""); s S.split("") S.split S "" StringBuffer ans = new StringBuffer(""); ans new StringBuffer("") while(N > 0) {
			int j = (int)((N-1)%26);
			N = (N-1)/26;
			ans.append(s[j]);
		} N > 0 N 0 {
			int j = (int)((N-1)%26);
			N = (N-1)/26;
			ans.append(s[j]);
		} int j = (int)((N-1)%26); j (int)((N-1)%26) (N-1) N 1 26 N = (N-1)/26 N (N-1)/26 (N-1) N 1 26 ans.append(s[j]) ans.append ans s[j] s j System.out.print(ans.reverse()) System.out.print System.out System System.out ans.reverse() ans.reverse ans keyboard.close() keyboard.close keyboard String[] args args public class Main {
public static void main(String[] args) {
		
		Scanner keyboard = new Scanner(System.in); 
		
		long N  = keyboard.nextLong();
		
		String S = "abcdefghijklmnopqrstuvwxyz";
		String[] s = S.split("");
		
		StringBuffer ans = new StringBuffer("");
		
		while(N > 0) {
			int j = (int)((N-1)%26);
			N = (N-1)/26;
			ans.append(s[j]);
		}
		
		System.out.print(ans.reverse());
		keyboard.close();	
	}
} public class Main {
public static void main(String[] args) {
		
		Scanner keyboard = new Scanner(System.in); 
		
		long N  = keyboard.nextLong();
		
		String S = "abcdefghijklmnopqrstuvwxyz";
		String[] s = S.split("");
		
		StringBuffer ans = new StringBuffer("");
		
		while(N > 0) {
			int j = (int)((N-1)%26);
			N = (N-1)/26;
			ans.append(s[j]);
		}
		
		System.out.print(ans.reverse());
		keyboard.close();	
	}
} Main
import java.util.*;

public class Main {
public static void main(String[] args) {
		
		Scanner keyboard = new Scanner(System.in); 
		
		long N  = keyboard.nextLong();
		
		String S = "abcdefghijklmnopqrstuvwxyz";
		String[] s = S.split("");
		
		StringBuffer ans = new StringBuffer("");
		
		while(N > 0) {
			int j = (int)((N-1)%26);
			N = (N-1)/26;
			ans.append(s[j]);
		}
		
		System.out.print(ans.reverse());
		keyboard.close();	
	}
}
