import java.util.*;

public class Main {

    public static void main(String[] args) {
	// write your code here
        Scanner sc = new Scanner(System.in);
        long inu = sc.nextLong();

        StringBuilder sb = new StringBuilder();
        while (inu > 0) {
            inu -= 1;
            long a = inu % 26;
            inu /= 26;
            char c = (char)(a + 'a');
            sb.insert(0, c);
        }

        System.out.println(sb.toString());
    }
} import java.util.*; util.* java public class Main {

    public static void main(String[] args) {
	// write your code here
        Scanner sc = new Scanner(System.in);
        long inu = sc.nextLong();

        StringBuilder sb = new StringBuilder();
        while (inu > 0) {
            inu -= 1;
            long a = inu % 26;
            inu /= 26;
            char c = (char)(a + 'a');
            sb.insert(0, c);
        }

        System.out.println(sb.toString());
    }
} Main public static void main(String[] args) {
	// write your code here
        Scanner sc = new Scanner(System.in);
        long inu = sc.nextLong();

        StringBuilder sb = new StringBuilder();
        while (inu > 0) {
            inu -= 1;
            long a = inu % 26;
            inu /= 26;
            char c = (char)(a + 'a');
            sb.insert(0, c);
        }

        System.out.println(sb.toString());
    } main {
	// write your code here
        Scanner sc = new Scanner(System.in);
        long inu = sc.nextLong();

        StringBuilder sb = new StringBuilder();
        while (inu > 0) {
            inu -= 1;
            long a = inu % 26;
            inu /= 26;
            char c = (char)(a + 'a');
            sb.insert(0, c);
        }

        System.out.println(sb.toString());
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long inu = sc.nextLong(); inu sc.nextLong() sc.nextLong sc StringBuilder sb = new StringBuilder(); sb new StringBuilder() while (inu > 0) {
            inu -= 1;
            long a = inu % 26;
            inu /= 26;
            char c = (char)(a + 'a');
            sb.insert(0, c);
        } inu > 0 inu 0 {
            inu -= 1;
            long a = inu % 26;
            inu /= 26;
            char c = (char)(a + 'a');
            sb.insert(0, c);
        } inu -= 1 inu 1 long a = inu % 26; a inu % 26 inu 26 inu /= 26 inu 26 char c = (char)(a + 'a'); c (char)(a + 'a') a 'a' sb.insert(0, c) sb.insert sb 0 c 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) {
	// write your code here
        Scanner sc = new Scanner(System.in);
        long inu = sc.nextLong();

        StringBuilder sb = new StringBuilder();
        while (inu > 0) {
            inu -= 1;
            long a = inu % 26;
            inu /= 26;
            char c = (char)(a + 'a');
            sb.insert(0, c);
        }

        System.out.println(sb.toString());
    }
} public class Main {

    public static void main(String[] args) {
	// write your code here
        Scanner sc = new Scanner(System.in);
        long inu = sc.nextLong();

        StringBuilder sb = new StringBuilder();
        while (inu > 0) {
            inu -= 1;
            long a = inu % 26;
            inu /= 26;
            char c = (char)(a + 'a');
            sb.insert(0, c);
        }

        System.out.println(sb.toString());
    }
} Main
import java.util.*;

public class Main {

    public static void main(String[] args) {
	// write your code here
        Scanner sc = new Scanner(System.in);
        long inu = sc.nextLong();

        StringBuilder sb = new StringBuilder();
        while (inu > 0) {
            inu -= 1;
            long a = inu % 26;
            inu /= 26;
            char c = (char)(a + 'a');
            sb.insert(0, c);
        }

        System.out.println(sb.toString());
    }
}