
import java.util.Scanner;

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.append((char)( 'a' + n % 26 ) );  // sb.append((char)( 97 + n % 26 ) );
			n = n / 26;
			//System.out.println(sb);
		}

		System.out.println(sb.reverse());

		sc.close();


	}
} import java.util.Scanner; Scanner 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.append((char)( 'a' + n % 26 ) );  // sb.append((char)( 97 + n % 26 ) );
			n = n / 26;
			//System.out.println(sb);
		}

		System.out.println(sb.reverse());

		sc.close();


	}
} 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.append((char)( 'a' + n % 26 ) );  // sb.append((char)( 97 + n % 26 ) );
			n = n / 26;
			//System.out.println(sb);
		}

		System.out.println(sb.reverse());

		sc.close();


	} main {

		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		StringBuilder sb = new StringBuilder();

		while(n > 0) {
			n--;
			sb.append((char)( 'a' + n % 26 ) );  // sb.append((char)( 97 + n % 26 ) );
			n = n / 26;
			//System.out.println(sb);
		}

		System.out.println(sb.reverse());

		sc.close();


	} 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.append((char)( 'a' + n % 26 ) );  // sb.append((char)( 97 + n % 26 ) );
			n = n / 26;
			//System.out.println(sb);
		} n > 0 n 0 {
			n--;
			sb.append((char)( 'a' + n % 26 ) );  // sb.append((char)( 97 + n % 26 ) );
			n = n / 26;
			//System.out.println(sb);
		} n-- n sb.append((char)( 'a' + n % 26 ) ) sb.append sb (char)( 'a' + n % 26 ) 'a' n % 26 n 26 n = n / 26 n n / 26 n 26 System.out.println(sb.reverse()) System.out.println System.out System System.out sb.reverse() sb.reverse sb sc.close() sc.close sc 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.append((char)( 'a' + n % 26 ) );  // sb.append((char)( 97 + n % 26 ) );
			n = n / 26;
			//System.out.println(sb);
		}

		System.out.println(sb.reverse());

		sc.close();


	}
} 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.append((char)( 'a' + n % 26 ) );  // sb.append((char)( 97 + n % 26 ) );
			n = n / 26;
			//System.out.println(sb);
		}

		System.out.println(sb.reverse());

		sc.close();


	}
} Main

import java.util.Scanner;

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.append((char)( 'a' + n % 26 ) );  // sb.append((char)( 97 + n % 26 ) );
			n = n / 26;
			//System.out.println(sb);
		}

		System.out.println(sb.reverse());

		sc.close();


	}
}