import java.math.BigDecimal;
import java.util.*;

public class Main {

    Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        new Main().run();
    }

    void run() {

        long n = sc.nextLong();

        StringBuilder sb = new StringBuilder();

        while (n != 0) {
            long remain = n % 26;
            n /= 26;
            char c = remain==0 ? 'z' : (char)(remain+96);
            if (remain==0) n--;
            sb.append(c);
        }

        sb = sb.reverse();

        System.out.print(sb.toString());

    }
} import java.math.BigDecimal; BigDecimal java.math import java.util.*; util.* java public class Main {

    Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        new Main().run();
    }

    void run() {

        long n = sc.nextLong();

        StringBuilder sb = new StringBuilder();

        while (n != 0) {
            long remain = n % 26;
            n /= 26;
            char c = remain==0 ? 'z' : (char)(remain+96);
            if (remain==0) n--;
            sb.append(c);
        }

        sb = sb.reverse();

        System.out.print(sb.toString());

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

        long n = sc.nextLong();

        StringBuilder sb = new StringBuilder();

        while (n != 0) {
            long remain = n % 26;
            n /= 26;
            char c = remain==0 ? 'z' : (char)(remain+96);
            if (remain==0) n--;
            sb.append(c);
        }

        sb = sb.reverse();

        System.out.print(sb.toString());

    } run {

        long n = sc.nextLong();

        StringBuilder sb = new StringBuilder();

        while (n != 0) {
            long remain = n % 26;
            n /= 26;
            char c = remain==0 ? 'z' : (char)(remain+96);
            if (remain==0) n--;
            sb.append(c);
        }

        sb = sb.reverse();

        System.out.print(sb.toString());

    } long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc StringBuilder sb = new StringBuilder(); sb new StringBuilder() while (n != 0) {
            long remain = n % 26;
            n /= 26;
            char c = remain==0 ? 'z' : (char)(remain+96);
            if (remain==0) n--;
            sb.append(c);
        } n != 0 n 0 {
            long remain = n % 26;
            n /= 26;
            char c = remain==0 ? 'z' : (char)(remain+96);
            if (remain==0) n--;
            sb.append(c);
        } long remain = n % 26; remain n % 26 n 26 n /= 26 n 26 char c = remain==0 ? 'z' : (char)(remain+96); c remain==0 ? 'z' : (char)(remain+96) remain==0 remain 0 'z' (char)(remain+96) remain 96 if (remain==0) n--; remain==0 remain 0 n-- n sb.append(c) sb.append sb c sb = sb.reverse() sb sb.reverse() sb.reverse sb System.out.print(sb.toString()) System.out.print System.out System System.out sb.toString() sb.toString sb public class Main {

    Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        new Main().run();
    }

    void run() {

        long n = sc.nextLong();

        StringBuilder sb = new StringBuilder();

        while (n != 0) {
            long remain = n % 26;
            n /= 26;
            char c = remain==0 ? 'z' : (char)(remain+96);
            if (remain==0) n--;
            sb.append(c);
        }

        sb = sb.reverse();

        System.out.print(sb.toString());

    }
} public class Main {

    Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        new Main().run();
    }

    void run() {

        long n = sc.nextLong();

        StringBuilder sb = new StringBuilder();

        while (n != 0) {
            long remain = n % 26;
            n /= 26;
            char c = remain==0 ? 'z' : (char)(remain+96);
            if (remain==0) n--;
            sb.append(c);
        }

        sb = sb.reverse();

        System.out.print(sb.toString());

    }
} Main
import java.math.BigDecimal;
import java.util.*;

public class Main {

    Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        new Main().run();
    }

    void run() {

        long n = sc.nextLong();

        StringBuilder sb = new StringBuilder();

        while (n != 0) {
            long remain = n % 26;
            n /= 26;
            char c = remain==0 ? 'z' : (char)(remain+96);
            if (remain==0) n--;
            sb.append(c);
        }

        sb = sb.reverse();

        System.out.print(sb.toString());

    }
}
