import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

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

		long index[] = new long[100];
		index[0] = 1;
		for (int i = 1; i < 11; i++) {
			index[i] = index[i-1] + (long)Math.pow(26, i);
		}
		StringBuilder sb = new StringBuilder();
		for (int i = 10; i >= 0 ; i--) {
			int w = (int)(n/index[i]);
			if (w > 0) {
				long temp = (long)Math.pow(26, i);
				int x = (int)(((n-index[i])/temp));
				sb.append((char)(x + 'a'));
				n= n - (x+1)*temp;
			}
		}
		System.out.println(sb.toString());
	}

}
 import java.util.ArrayList; ArrayList java.util import java.util.List; List java.util 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();

		long index[] = new long[100];
		index[0] = 1;
		for (int i = 1; i < 11; i++) {
			index[i] = index[i-1] + (long)Math.pow(26, i);
		}
		StringBuilder sb = new StringBuilder();
		for (int i = 10; i >= 0 ; i--) {
			int w = (int)(n/index[i]);
			if (w > 0) {
				long temp = (long)Math.pow(26, i);
				int x = (int)(((n-index[i])/temp));
				sb.append((char)(x + 'a'));
				n= n - (x+1)*temp;
			}
		}
		System.out.println(sb.toString());
	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();

		long index[] = new long[100];
		index[0] = 1;
		for (int i = 1; i < 11; i++) {
			index[i] = index[i-1] + (long)Math.pow(26, i);
		}
		StringBuilder sb = new StringBuilder();
		for (int i = 10; i >= 0 ; i--) {
			int w = (int)(n/index[i]);
			if (w > 0) {
				long temp = (long)Math.pow(26, i);
				int x = (int)(((n-index[i])/temp));
				sb.append((char)(x + 'a'));
				n= n - (x+1)*temp;
			}
		}
		System.out.println(sb.toString());
	} main {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();

		long index[] = new long[100];
		index[0] = 1;
		for (int i = 1; i < 11; i++) {
			index[i] = index[i-1] + (long)Math.pow(26, i);
		}
		StringBuilder sb = new StringBuilder();
		for (int i = 10; i >= 0 ; i--) {
			int w = (int)(n/index[i]);
			if (w > 0) {
				long temp = (long)Math.pow(26, i);
				int x = (int)(((n-index[i])/temp));
				sb.append((char)(x + 'a'));
				n= n - (x+1)*temp;
			}
		}
		System.out.println(sb.toString());
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc long index[] = new long[100]; index new long[100] 100 index[0] = 1 index[0] index 0 1 for (int i = 1; i < 11; i++) {
			index[i] = index[i-1] + (long)Math.pow(26, i);
		} int i = 1; int i = 1; i 1 i < 11 i 11 i++ i++ i {
			index[i] = index[i-1] + (long)Math.pow(26, i);
		} {
			index[i] = index[i-1] + (long)Math.pow(26, i);
		} index[i] = index[i-1] + (long)Math.pow(26, i) index[i] index i index[i-1] + (long)Math.pow(26, i) index[i-1] index i-1 i 1 (long)Math.pow(26, i) Math.pow Math 26 i StringBuilder sb = new StringBuilder(); sb new StringBuilder() for (int i = 10; i >= 0 ; i--) {
			int w = (int)(n/index[i]);
			if (w > 0) {
				long temp = (long)Math.pow(26, i);
				int x = (int)(((n-index[i])/temp));
				sb.append((char)(x + 'a'));
				n= n - (x+1)*temp;
			}
		} int i = 10; int i = 10; i 10 i >= 0 i 0 i-- i-- i {
			int w = (int)(n/index[i]);
			if (w > 0) {
				long temp = (long)Math.pow(26, i);
				int x = (int)(((n-index[i])/temp));
				sb.append((char)(x + 'a'));
				n= n - (x+1)*temp;
			}
		} {
			int w = (int)(n/index[i]);
			if (w > 0) {
				long temp = (long)Math.pow(26, i);
				int x = (int)(((n-index[i])/temp));
				sb.append((char)(x + 'a'));
				n= n - (x+1)*temp;
			}
		} int w = (int)(n/index[i]); w (int)(n/index[i]) n index[i] index i if (w > 0) {
				long temp = (long)Math.pow(26, i);
				int x = (int)(((n-index[i])/temp));
				sb.append((char)(x + 'a'));
				n= n - (x+1)*temp;
			} w > 0 w 0 {
				long temp = (long)Math.pow(26, i);
				int x = (int)(((n-index[i])/temp));
				sb.append((char)(x + 'a'));
				n= n - (x+1)*temp;
			} long temp = (long)Math.pow(26, i); temp (long)Math.pow(26, i) Math.pow Math 26 i int x = (int)(((n-index[i])/temp)); x (int)(((n-index[i])/temp)) (n-index[i]) n index[i] index i temp sb.append((char)(x + 'a')) sb.append sb (char)(x + 'a') x 'a' n= n - (x+1)*temp n n - (x+1)*temp n (x+1)*temp (x+1) x 1 temp System.out.println(sb.toString()) System.out.println System.out System System.out sb.toString() sb.toString sb String[] args args public class Main {

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

		long index[] = new long[100];
		index[0] = 1;
		for (int i = 1; i < 11; i++) {
			index[i] = index[i-1] + (long)Math.pow(26, i);
		}
		StringBuilder sb = new StringBuilder();
		for (int i = 10; i >= 0 ; i--) {
			int w = (int)(n/index[i]);
			if (w > 0) {
				long temp = (long)Math.pow(26, i);
				int x = (int)(((n-index[i])/temp));
				sb.append((char)(x + 'a'));
				n= n - (x+1)*temp;
			}
		}
		System.out.println(sb.toString());
	}

} public class Main {

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

		long index[] = new long[100];
		index[0] = 1;
		for (int i = 1; i < 11; i++) {
			index[i] = index[i-1] + (long)Math.pow(26, i);
		}
		StringBuilder sb = new StringBuilder();
		for (int i = 10; i >= 0 ; i--) {
			int w = (int)(n/index[i]);
			if (w > 0) {
				long temp = (long)Math.pow(26, i);
				int x = (int)(((n-index[i])/temp));
				sb.append((char)(x + 'a'));
				n= n - (x+1)*temp;
			}
		}
		System.out.println(sb.toString());
	}

} Main
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

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

		long index[] = new long[100];
		index[0] = 1;
		for (int i = 1; i < 11; i++) {
			index[i] = index[i-1] + (long)Math.pow(26, i);
		}
		StringBuilder sb = new StringBuilder();
		for (int i = 10; i >= 0 ; i--) {
			int w = (int)(n/index[i]);
			if (w > 0) {
				long temp = (long)Math.pow(26, i);
				int x = (int)(((n-index[i])/temp));
				sb.append((char)(x + 'a'));
				n= n - (x+1)*temp;
			}
		}
		System.out.println(sb.toString());
	}

}

