import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        long N = scanner.nextLong();
        long[] num = new long[50];
        int k = 0;
        while(N > 0) {
            num[++k] = (N - 1) % 26;
            N--;
            N /= 26;
        }
        String ans = "";
        for (int i = k; i > 0; i--) {
            char c = (char) (97 + num[i]);
            ans += c;
        }
        System.out.println(ans);
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        long N = scanner.nextLong();
        long[] num = new long[50];
        int k = 0;
        while(N > 0) {
            num[++k] = (N - 1) % 26;
            N--;
            N /= 26;
        }
        String ans = "";
        for (int i = k; i > 0; i--) {
            char c = (char) (97 + num[i]);
            ans += c;
        }
        System.out.println(ans);
    }
} Main public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        long N = scanner.nextLong();
        long[] num = new long[50];
        int k = 0;
        while(N > 0) {
            num[++k] = (N - 1) % 26;
            N--;
            N /= 26;
        }
        String ans = "";
        for (int i = k; i > 0; i--) {
            char c = (char) (97 + num[i]);
            ans += c;
        }
        System.out.println(ans);
    } main {
        Scanner scanner = new Scanner(System.in);

        long N = scanner.nextLong();
        long[] num = new long[50];
        int k = 0;
        while(N > 0) {
            num[++k] = (N - 1) % 26;
            N--;
            N /= 26;
        }
        String ans = "";
        for (int i = k; i > 0; i--) {
            char c = (char) (97 + num[i]);
            ans += c;
        }
        System.out.println(ans);
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) long N = scanner.nextLong(); N scanner.nextLong() scanner.nextLong scanner long[] num = new long[50]; num new long[50] 50 int k = 0; k 0 while(N > 0) {
            num[++k] = (N - 1) % 26;
            N--;
            N /= 26;
        } N > 0 N 0 {
            num[++k] = (N - 1) % 26;
            N--;
            N /= 26;
        } num[++k] = (N - 1) % 26 num[++k] num ++k k (N - 1) % 26 (N - 1) N 1 26 N-- N N /= 26 N 26 String ans = ""; ans "" for (int i = k; i > 0; i--) {
            char c = (char) (97 + num[i]);
            ans += c;
        } int i = k; int i = k; i k i > 0 i 0 i-- i-- i {
            char c = (char) (97 + num[i]);
            ans += c;
        } {
            char c = (char) (97 + num[i]);
            ans += c;
        } char c = (char) (97 + num[i]); c (char) (97 + num[i]) 97 num[i] num i ans += c ans c 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) {
        Scanner scanner = new Scanner(System.in);

        long N = scanner.nextLong();
        long[] num = new long[50];
        int k = 0;
        while(N > 0) {
            num[++k] = (N - 1) % 26;
            N--;
            N /= 26;
        }
        String ans = "";
        for (int i = k; i > 0; i--) {
            char c = (char) (97 + num[i]);
            ans += c;
        }
        System.out.println(ans);
    }
} public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        long N = scanner.nextLong();
        long[] num = new long[50];
        int k = 0;
        while(N > 0) {
            num[++k] = (N - 1) % 26;
            N--;
            N /= 26;
        }
        String ans = "";
        for (int i = k; i > 0; i--) {
            char c = (char) (97 + num[i]);
            ans += c;
        }
        System.out.println(ans);
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        long N = scanner.nextLong();
        long[] num = new long[50];
        int k = 0;
        while(N > 0) {
            num[++k] = (N - 1) % 26;
            N--;
            N /= 26;
        }
        String ans = "";
        for (int i = k; i > 0; i--) {
            char c = (char) (97 + num[i]);
            ans += c;
        }
        System.out.println(ans);
    }
}