import java.util.Scanner;

public class Main {
    public static void main(String args[]) {
        Scanner scan = new Scanner(System.in);

        long n = scan.nextLong();

        StringBuilder name = new StringBuilder();
        int surplus;
        for (; n > 0; n = (n - 1) / 26) {
            surplus = (int) ((n - 1) % 26);
            name.append((char) (surplus + 'a'));
        }
        
        for (int i = name.length(); i > 0; --i) {
            System.out.print(name.charAt(i - 1));
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String args[]) {
        Scanner scan = new Scanner(System.in);

        long n = scan.nextLong();

        StringBuilder name = new StringBuilder();
        int surplus;
        for (; n > 0; n = (n - 1) / 26) {
            surplus = (int) ((n - 1) % 26);
            name.append((char) (surplus + 'a'));
        }
        
        for (int i = name.length(); i > 0; --i) {
            System.out.print(name.charAt(i - 1));
        }
    }
} Main public static void main(String args[]) {
        Scanner scan = new Scanner(System.in);

        long n = scan.nextLong();

        StringBuilder name = new StringBuilder();
        int surplus;
        for (; n > 0; n = (n - 1) / 26) {
            surplus = (int) ((n - 1) % 26);
            name.append((char) (surplus + 'a'));
        }
        
        for (int i = name.length(); i > 0; --i) {
            System.out.print(name.charAt(i - 1));
        }
    } main {
        Scanner scan = new Scanner(System.in);

        long n = scan.nextLong();

        StringBuilder name = new StringBuilder();
        int surplus;
        for (; n > 0; n = (n - 1) / 26) {
            surplus = (int) ((n - 1) % 26);
            name.append((char) (surplus + 'a'));
        }
        
        for (int i = name.length(); i > 0; --i) {
            System.out.print(name.charAt(i - 1));
        }
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) long n = scan.nextLong(); n scan.nextLong() scan.nextLong scan StringBuilder name = new StringBuilder(); name new StringBuilder() int surplus; surplus for (; n > 0; n = (n - 1) / 26) {
            surplus = (int) ((n - 1) % 26);
            name.append((char) (surplus + 'a'));
        } ; n > 0 n 0 n = (n - 1) / 26 n = (n - 1) / 26 n (n - 1) / 26 (n - 1) n 1 26 {
            surplus = (int) ((n - 1) % 26);
            name.append((char) (surplus + 'a'));
        } {
            surplus = (int) ((n - 1) % 26);
            name.append((char) (surplus + 'a'));
        } surplus = (int) ((n - 1) % 26) surplus (int) ((n - 1) % 26) (n - 1) n 1 26 name.append((char) (surplus + 'a')) name.append name (char) (surplus + 'a') surplus 'a' for (int i = name.length(); i > 0; --i) {
            System.out.print(name.charAt(i - 1));
        } int i = name.length(); int i = name.length(); i name.length() name.length name i > 0 i 0 --i --i i {
            System.out.print(name.charAt(i - 1));
        } {
            System.out.print(name.charAt(i - 1));
        } System.out.print(name.charAt(i - 1)) System.out.print System.out System System.out name.charAt(i - 1) name.charAt name i - 1 i 1 String args[] args public class Main {
    public static void main(String args[]) {
        Scanner scan = new Scanner(System.in);

        long n = scan.nextLong();

        StringBuilder name = new StringBuilder();
        int surplus;
        for (; n > 0; n = (n - 1) / 26) {
            surplus = (int) ((n - 1) % 26);
            name.append((char) (surplus + 'a'));
        }
        
        for (int i = name.length(); i > 0; --i) {
            System.out.print(name.charAt(i - 1));
        }
    }
} public class Main {
    public static void main(String args[]) {
        Scanner scan = new Scanner(System.in);

        long n = scan.nextLong();

        StringBuilder name = new StringBuilder();
        int surplus;
        for (; n > 0; n = (n - 1) / 26) {
            surplus = (int) ((n - 1) % 26);
            name.append((char) (surplus + 'a'));
        }
        
        for (int i = name.length(); i > 0; --i) {
            System.out.print(name.charAt(i - 1));
        }
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String args[]) {
        Scanner scan = new Scanner(System.in);

        long n = scan.nextLong();

        StringBuilder name = new StringBuilder();
        int surplus;
        for (; n > 0; n = (n - 1) / 26) {
            surplus = (int) ((n - 1) % 26);
            name.append((char) (surplus + 'a'));
        }
        
        for (int i = name.length(); i > 0; --i) {
            System.out.print(name.charAt(i - 1));
        }
    }
}