import java.io.*;
import java.math.*;
import java.util.*;
public class Main {
 
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		long N = input.nextLong();
		String ans = "";
		Stack<Character> seq = new Stack<Character>();
		while (N>0) {
			N--;
			char cur = (char)(N%26+97);
			seq.push(cur);
			N/=26;
		}
		while (!seq.isEmpty()) {
			char cur = seq.pop();
			System.out.print(cur);
		}
	}
} import java.io.*; io.* java import java.math.*; math.* java import java.util.*; util.* java public class Main {
 
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		long N = input.nextLong();
		String ans = "";
		Stack<Character> seq = new Stack<Character>();
		while (N>0) {
			N--;
			char cur = (char)(N%26+97);
			seq.push(cur);
			N/=26;
		}
		while (!seq.isEmpty()) {
			char cur = seq.pop();
			System.out.print(cur);
		}
	}
} Main public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		long N = input.nextLong();
		String ans = "";
		Stack<Character> seq = new Stack<Character>();
		while (N>0) {
			N--;
			char cur = (char)(N%26+97);
			seq.push(cur);
			N/=26;
		}
		while (!seq.isEmpty()) {
			char cur = seq.pop();
			System.out.print(cur);
		}
	} main {
		Scanner input = new Scanner(System.in);
		long N = input.nextLong();
		String ans = "";
		Stack<Character> seq = new Stack<Character>();
		while (N>0) {
			N--;
			char cur = (char)(N%26+97);
			seq.push(cur);
			N/=26;
		}
		while (!seq.isEmpty()) {
			char cur = seq.pop();
			System.out.print(cur);
		}
	} Scanner input = new Scanner(System.in); input new Scanner(System.in) long N = input.nextLong(); N input.nextLong() input.nextLong input String ans = ""; ans "" Stack<Character> seq = new Stack<Character>(); seq new Stack<Character>() while (N>0) {
			N--;
			char cur = (char)(N%26+97);
			seq.push(cur);
			N/=26;
		} N>0 N 0 {
			N--;
			char cur = (char)(N%26+97);
			seq.push(cur);
			N/=26;
		} N-- N char cur = (char)(N%26+97); cur (char)(N%26+97) N%26 N 26 97 seq.push(cur) seq.push seq cur N/=26 N 26 while (!seq.isEmpty()) {
			char cur = seq.pop();
			System.out.print(cur);
		} !seq.isEmpty() seq.isEmpty() seq.isEmpty seq {
			char cur = seq.pop();
			System.out.print(cur);
		} char cur = seq.pop(); cur seq.pop() seq.pop seq System.out.print(cur) System.out.print System.out System System.out cur String[] args args public class Main {
 
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		long N = input.nextLong();
		String ans = "";
		Stack<Character> seq = new Stack<Character>();
		while (N>0) {
			N--;
			char cur = (char)(N%26+97);
			seq.push(cur);
			N/=26;
		}
		while (!seq.isEmpty()) {
			char cur = seq.pop();
			System.out.print(cur);
		}
	}
} public class Main {
 
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		long N = input.nextLong();
		String ans = "";
		Stack<Character> seq = new Stack<Character>();
		while (N>0) {
			N--;
			char cur = (char)(N%26+97);
			seq.push(cur);
			N/=26;
		}
		while (!seq.isEmpty()) {
			char cur = seq.pop();
			System.out.print(cur);
		}
	}
} Main
import java.io.*;
import java.math.*;
import java.util.*;
public class Main {
 
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		long N = input.nextLong();
		String ans = "";
		Stack<Character> seq = new Stack<Character>();
		while (N>0) {
			N--;
			char cur = (char)(N%26+97);
			seq.push(cur);
			N/=26;
		}
		while (!seq.isEmpty()) {
			char cur = seq.pop();
			System.out.print(cur);
		}
	}
}