import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            long N = Long.parseLong(sc.next());
            StringBuilder ans = new StringBuilder();
            while(N > 0) {
                N--;
                ans.insert(0, (char) ('a' + (N % 26)));
                N /= 26;
            }
            System.out.println(ans);
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            long N = Long.parseLong(sc.next());
            StringBuilder ans = new StringBuilder();
            while(N > 0) {
                N--;
                ans.insert(0, (char) ('a' + (N % 26)));
                N /= 26;
            }
            System.out.println(ans);
        }
    }
} Main public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            long N = Long.parseLong(sc.next());
            StringBuilder ans = new StringBuilder();
            while(N > 0) {
                N--;
                ans.insert(0, (char) ('a' + (N % 26)));
                N /= 26;
            }
            System.out.println(ans);
        }
    } main {
        try (Scanner sc = new Scanner(System.in)) {
            long N = Long.parseLong(sc.next());
            StringBuilder ans = new StringBuilder();
            while(N > 0) {
                N--;
                ans.insert(0, (char) ('a' + (N % 26)));
                N /= 26;
            }
            System.out.println(ans);
        }
    } try (Scanner sc = new Scanner(System.in)) {
            long N = Long.parseLong(sc.next());
            StringBuilder ans = new StringBuilder();
            while(N > 0) {
                N--;
                ans.insert(0, (char) ('a' + (N % 26)));
                N /= 26;
            }
            System.out.println(ans);
        } {
            long N = Long.parseLong(sc.next());
            StringBuilder ans = new StringBuilder();
            while(N > 0) {
                N--;
                ans.insert(0, (char) ('a' + (N % 26)));
                N /= 26;
            }
            System.out.println(ans);
        } Scanner sc = new Scanner(System.in) Scanner sc = new Scanner(System.in) new Scanner(System.in) long N = Long.parseLong(sc.next()); N Long.parseLong(sc.next()) Long.parseLong Long sc.next() sc.next sc StringBuilder ans = new StringBuilder(); ans new StringBuilder() while(N > 0) {
                N--;
                ans.insert(0, (char) ('a' + (N % 26)));
                N /= 26;
            } N > 0 N 0 {
                N--;
                ans.insert(0, (char) ('a' + (N % 26)));
                N /= 26;
            } N-- N ans.insert(0, (char) ('a' + (N % 26))) ans.insert ans 0 (char) ('a' + (N % 26)) 'a' (N % 26) N 26 N /= 26 N 26 System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            long N = Long.parseLong(sc.next());
            StringBuilder ans = new StringBuilder();
            while(N > 0) {
                N--;
                ans.insert(0, (char) ('a' + (N % 26)));
                N /= 26;
            }
            System.out.println(ans);
        }
    }
} public class Main {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            long N = Long.parseLong(sc.next());
            StringBuilder ans = new StringBuilder();
            while(N > 0) {
                N--;
                ans.insert(0, (char) ('a' + (N % 26)));
                N /= 26;
            }
            System.out.println(ans);
        }
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            long N = Long.parseLong(sc.next());
            StringBuilder ans = new StringBuilder();
            while(N > 0) {
                N--;
                ans.insert(0, (char) ('a' + (N % 26)));
                N /= 26;
            }
            System.out.println(ans);
        }
    }
}