import java.util.*;

public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        StringBuilder builder = new StringBuilder();
        while (n > 0) {
            long e = (n - 1) % 26;
            char v = (char) (e + 97);
            builder.insert(0, v);
            if (e == 25) {
                n--;
            }
            n /= 26;
        }
        System.out.println(builder);
    }
} 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 n = sc.nextLong();
        StringBuilder builder = new StringBuilder();
        while (n > 0) {
            long e = (n - 1) % 26;
            char v = (char) (e + 97);
            builder.insert(0, v);
            if (e == 25) {
                n--;
            }
            n /= 26;
        }
        System.out.println(builder);
    }
} Main public static void main(String[] args) {
        // write your code here
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        StringBuilder builder = new StringBuilder();
        while (n > 0) {
            long e = (n - 1) % 26;
            char v = (char) (e + 97);
            builder.insert(0, v);
            if (e == 25) {
                n--;
            }
            n /= 26;
        }
        System.out.println(builder);
    } main {
        // write your code here
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        StringBuilder builder = new StringBuilder();
        while (n > 0) {
            long e = (n - 1) % 26;
            char v = (char) (e + 97);
            builder.insert(0, v);
            if (e == 25) {
                n--;
            }
            n /= 26;
        }
        System.out.println(builder);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc StringBuilder builder = new StringBuilder(); builder new StringBuilder() while (n > 0) {
            long e = (n - 1) % 26;
            char v = (char) (e + 97);
            builder.insert(0, v);
            if (e == 25) {
                n--;
            }
            n /= 26;
        } n > 0 n 0 {
            long e = (n - 1) % 26;
            char v = (char) (e + 97);
            builder.insert(0, v);
            if (e == 25) {
                n--;
            }
            n /= 26;
        } long e = (n - 1) % 26; e (n - 1) % 26 (n - 1) n 1 26 char v = (char) (e + 97); v (char) (e + 97) e 97 builder.insert(0, v) builder.insert builder 0 v if (e == 25) {
                n--;
            } e == 25 e 25 {
                n--;
            } n-- n n /= 26 n 26 System.out.println(builder) System.out.println System.out System System.out builder String[] args args public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        StringBuilder builder = new StringBuilder();
        while (n > 0) {
            long e = (n - 1) % 26;
            char v = (char) (e + 97);
            builder.insert(0, v);
            if (e == 25) {
                n--;
            }
            n /= 26;
        }
        System.out.println(builder);
    }
} public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        StringBuilder builder = new StringBuilder();
        while (n > 0) {
            long e = (n - 1) % 26;
            char v = (char) (e + 97);
            builder.insert(0, v);
            if (e == 25) {
                n--;
            }
            n /= 26;
        }
        System.out.println(builder);
    }
} Main
import java.util.*;

public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        StringBuilder builder = new StringBuilder();
        while (n > 0) {
            long e = (n - 1) % 26;
            char v = (char) (e + 97);
            builder.insert(0, v);
            if (e == 25) {
                n--;
            }
            n /= 26;
        }
        System.out.println(builder);
    }
}