// 提出時に消す


import java.util.Scanner;

// 提出時にMainに変更する
public class Main {

    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);

        long n = sc.nextLong();

        StringBuilder ans = new StringBuilder();

        while (n != 0) {
            n--;
            ans.append((char) ('a' + n % 26));
            n /= 26;
        }

        ans = ans.reverse();

        System.out.println(ans);

        sc.close();
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);

        long n = sc.nextLong();

        StringBuilder ans = new StringBuilder();

        while (n != 0) {
            n--;
            ans.append((char) ('a' + n % 26));
            n /= 26;
        }

        ans = ans.reverse();

        System.out.println(ans);

        sc.close();
    }
} Main public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);

        long n = sc.nextLong();

        StringBuilder ans = new StringBuilder();

        while (n != 0) {
            n--;
            ans.append((char) ('a' + n % 26));
            n /= 26;
        }

        ans = ans.reverse();

        System.out.println(ans);

        sc.close();
    } main {
        Scanner sc = new Scanner(System.in);

        long n = sc.nextLong();

        StringBuilder ans = new StringBuilder();

        while (n != 0) {
            n--;
            ans.append((char) ('a' + n % 26));
            n /= 26;
        }

        ans = ans.reverse();

        System.out.println(ans);

        sc.close();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc StringBuilder ans = new StringBuilder(); ans new StringBuilder() while (n != 0) {
            n--;
            ans.append((char) ('a' + n % 26));
            n /= 26;
        } n != 0 n 0 {
            n--;
            ans.append((char) ('a' + n % 26));
            n /= 26;
        } n-- n ans.append((char) ('a' + n % 26)) ans.append ans (char) ('a' + n % 26) 'a' n % 26 n 26 n /= 26 n 26 ans = ans.reverse() ans ans.reverse() ans.reverse ans System.out.println(ans) System.out.println System.out System System.out ans sc.close() sc.close sc String[] args args public class Main {

    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);

        long n = sc.nextLong();

        StringBuilder ans = new StringBuilder();

        while (n != 0) {
            n--;
            ans.append((char) ('a' + n % 26));
            n /= 26;
        }

        ans = ans.reverse();

        System.out.println(ans);

        sc.close();
    }
} public class Main {

    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);

        long n = sc.nextLong();

        StringBuilder ans = new StringBuilder();

        while (n != 0) {
            n--;
            ans.append((char) ('a' + n % 26));
            n /= 26;
        }

        ans = ans.reverse();

        System.out.println(ans);

        sc.close();
    }
} Main
// 提出時に消す


import java.util.Scanner;

// 提出時にMainに変更する
public class Main {

    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);

        long n = sc.nextLong();

        StringBuilder ans = new StringBuilder();

        while (n != 0) {
            n--;
            ans.append((char) ('a' + n % 26));
            n /= 26;
        }

        ans = ans.reverse();

        System.out.println(ans);

        sc.close();
    }
}