import java.util.Scanner;

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

        String s = "";

        while(n > 0) {
            n--;
            s = (char)('a' + n % 26) + s;
            n /= 26;
        }
        System.out.println(s);
    }
} 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();
        sc.close();

        String s = "";

        while(n > 0) {
            n--;
            s = (char)('a' + n % 26) + s;
            n /= 26;
        }
        System.out.println(s);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        sc.close();

        String s = "";

        while(n > 0) {
            n--;
            s = (char)('a' + n % 26) + s;
            n /= 26;
        }
        System.out.println(s);
    } main {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        sc.close();

        String s = "";

        while(n > 0) {
            n--;
            s = (char)('a' + n % 26) + s;
            n /= 26;
        }
        System.out.println(s);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc sc.close() sc.close sc String s = ""; s "" while(n > 0) {
            n--;
            s = (char)('a' + n % 26) + s;
            n /= 26;
        } n > 0 n 0 {
            n--;
            s = (char)('a' + n % 26) + s;
            n /= 26;
        } n-- n s = (char)('a' + n % 26) + s s (char)('a' + n % 26) + s (char)('a' + n % 26) 'a' n % 26 n 26 s n /= 26 n 26 System.out.println(s) System.out.println System.out System System.out s String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        sc.close();

        String s = "";

        while(n > 0) {
            n--;
            s = (char)('a' + n % 26) + s;
            n /= 26;
        }
        System.out.println(s);
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        sc.close();

        String s = "";

        while(n > 0) {
            n--;
            s = (char)('a' + n % 26) + s;
            n /= 26;
        }
        System.out.println(s);
    }
} Main
import java.util.Scanner;

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

        String s = "";

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