import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws IOException {
        final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));


        long n = Long.parseLong(br.readLine());
        StringBuilder sb = new StringBuilder();
        int position = 26;

        while (n > 0) {
            int letter = (int)((n - 1) % 26 + 1);
            sb.append((char)('a' + letter - 1));
            n -= letter;
            n /= 26;
        }

        bw.write(sb.reverse().toString());
        bw.newLine();

        bw.close();
        br.close();
    }
} import java.util.*; util.* java import java.io.*; io.* java public class Main {
    public static void main(String[] args) throws IOException {
        final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));


        long n = Long.parseLong(br.readLine());
        StringBuilder sb = new StringBuilder();
        int position = 26;

        while (n > 0) {
            int letter = (int)((n - 1) % 26 + 1);
            sb.append((char)('a' + letter - 1));
            n -= letter;
            n /= 26;
        }

        bw.write(sb.reverse().toString());
        bw.newLine();

        bw.close();
        br.close();
    }
} Main public static void main(String[] args) throws IOException {
        final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));


        long n = Long.parseLong(br.readLine());
        StringBuilder sb = new StringBuilder();
        int position = 26;

        while (n > 0) {
            int letter = (int)((n - 1) % 26 + 1);
            sb.append((char)('a' + letter - 1));
            n -= letter;
            n /= 26;
        }

        bw.write(sb.reverse().toString());
        bw.newLine();

        bw.close();
        br.close();
    } main {
        final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));


        long n = Long.parseLong(br.readLine());
        StringBuilder sb = new StringBuilder();
        int position = 26;

        while (n > 0) {
            int letter = (int)((n - 1) % 26 + 1);
            sb.append((char)('a' + letter - 1));
            n -= letter;
            n /= 26;
        }

        bw.write(sb.reverse().toString());
        bw.newLine();

        bw.close();
        br.close();
    } final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out)); bw new BufferedWriter(new OutputStreamWriter(System.out)) final BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) long n = Long.parseLong(br.readLine()); n Long.parseLong(br.readLine()) Long.parseLong Long br.readLine() br.readLine br StringBuilder sb = new StringBuilder(); sb new StringBuilder() int position = 26; position 26 while (n > 0) {
            int letter = (int)((n - 1) % 26 + 1);
            sb.append((char)('a' + letter - 1));
            n -= letter;
            n /= 26;
        } n > 0 n 0 {
            int letter = (int)((n - 1) % 26 + 1);
            sb.append((char)('a' + letter - 1));
            n -= letter;
            n /= 26;
        } int letter = (int)((n - 1) % 26 + 1); letter (int)((n - 1) % 26 + 1) (n - 1) % 26 (n - 1) n 1 26 1 sb.append((char)('a' + letter - 1)) sb.append sb (char)('a' + letter - 1) 'a' + letter 'a' letter 1 n -= letter n letter n /= 26 n 26 bw.write(sb.reverse().toString()) bw.write bw sb.reverse().toString() sb.reverse().toString sb.reverse() sb.reverse sb bw.newLine() bw.newLine bw bw.close() bw.close bw br.close() br.close br String[] args args public class Main {
    public static void main(String[] args) throws IOException {
        final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));


        long n = Long.parseLong(br.readLine());
        StringBuilder sb = new StringBuilder();
        int position = 26;

        while (n > 0) {
            int letter = (int)((n - 1) % 26 + 1);
            sb.append((char)('a' + letter - 1));
            n -= letter;
            n /= 26;
        }

        bw.write(sb.reverse().toString());
        bw.newLine();

        bw.close();
        br.close();
    }
} public class Main {
    public static void main(String[] args) throws IOException {
        final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));


        long n = Long.parseLong(br.readLine());
        StringBuilder sb = new StringBuilder();
        int position = 26;

        while (n > 0) {
            int letter = (int)((n - 1) % 26 + 1);
            sb.append((char)('a' + letter - 1));
            n -= letter;
            n /= 26;
        }

        bw.write(sb.reverse().toString());
        bw.newLine();

        bw.close();
        br.close();
    }
} Main
import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws IOException {
        final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));


        long n = Long.parseLong(br.readLine());
        StringBuilder sb = new StringBuilder();
        int position = 26;

        while (n > 0) {
            int letter = (int)((n - 1) % 26 + 1);
            sb.append((char)('a' + letter - 1));
            n -= letter;
            n /= 26;
        }

        bw.write(sb.reverse().toString());
        bw.newLine();

        bw.close();
        br.close();
    }
}
