import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.*;
import java.awt.Point;

public class Main {
    // static int INF = (1 << 30) - 1;
    // static long L_INF = (1L << 62) - 1;
    // static long MOD = (long) 1e9 + 7;

    static class Solver {
        long N;
        // int[] A;

        // write your code
        void solve(InputReader in, PrintWriter out) {
            N = in.nextLong();
            ArrayList<Character> al = new ArrayList<>();
            while (N > 0) {
                long r = N % 26;
                char c = 'a';
                if (r == 0) {
                    c = 'z';
                } else {
                    c += (char) (r - 1);
                }
                al.add(c);
                if (r == 0) {
                    N--;
                }
                N /= 26;
            }

            Collections.reverse(al);
            for (Character c : al) {
                out.print(c);
            }
            out.println();
        }

        void debug(Object... os) {
            System.err.println(Arrays.deepToString(os));
        }
    }

    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(in, out);
        out.close();
    }

    static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.OutputStream; OutputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.*; util.* java import java.awt.Point; Point java.awt public class Main {
    // static int INF = (1 << 30) - 1;
    // static long L_INF = (1L << 62) - 1;
    // static long MOD = (long) 1e9 + 7;

    static class Solver {
        long N;
        // int[] A;

        // write your code
        void solve(InputReader in, PrintWriter out) {
            N = in.nextLong();
            ArrayList<Character> al = new ArrayList<>();
            while (N > 0) {
                long r = N % 26;
                char c = 'a';
                if (r == 0) {
                    c = 'z';
                } else {
                    c += (char) (r - 1);
                }
                al.add(c);
                if (r == 0) {
                    N--;
                }
                N /= 26;
            }

            Collections.reverse(al);
            for (Character c : al) {
                out.print(c);
            }
            out.println();
        }

        void debug(Object... os) {
            System.err.println(Arrays.deepToString(os));
        }
    }

    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(in, out);
        out.close();
    }

    static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }
    }
} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out InputReader in = new InputReader(inputStream); in new InputReader(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) Solver solver = new Solver(); solver new Solver() solver.solve(in, out) solver.solve solver in out out.close() out.close out String[] args args static class Solver {
        long N;
        // int[] A;

        // write your code
        void solve(InputReader in, PrintWriter out) {
            N = in.nextLong();
            ArrayList<Character> al = new ArrayList<>();
            while (N > 0) {
                long r = N % 26;
                char c = 'a';
                if (r == 0) {
                    c = 'z';
                } else {
                    c += (char) (r - 1);
                }
                al.add(c);
                if (r == 0) {
                    N--;
                }
                N /= 26;
            }

            Collections.reverse(al);
            for (Character c : al) {
                out.print(c);
            }
            out.println();
        }

        void debug(Object... os) {
            System.err.println(Arrays.deepToString(os));
        }
    } Solver long N; N // write your code
        void solve(InputReader in, PrintWriter out) {
            N = in.nextLong();
            ArrayList<Character> al = new ArrayList<>();
            while (N > 0) {
                long r = N % 26;
                char c = 'a';
                if (r == 0) {
                    c = 'z';
                } else {
                    c += (char) (r - 1);
                }
                al.add(c);
                if (r == 0) {
                    N--;
                }
                N /= 26;
            }

            Collections.reverse(al);
            for (Character c : al) {
                out.print(c);
            }
            out.println();
        } solve {
            N = in.nextLong();
            ArrayList<Character> al = new ArrayList<>();
            while (N > 0) {
                long r = N % 26;
                char c = 'a';
                if (r == 0) {
                    c = 'z';
                } else {
                    c += (char) (r - 1);
                }
                al.add(c);
                if (r == 0) {
                    N--;
                }
                N /= 26;
            }

            Collections.reverse(al);
            for (Character c : al) {
                out.print(c);
            }
            out.println();
        } N = in.nextLong() N in.nextLong() in.nextLong in ArrayList<Character> al = new ArrayList<>(); al new ArrayList<>() while (N > 0) {
                long r = N % 26;
                char c = 'a';
                if (r == 0) {
                    c = 'z';
                } else {
                    c += (char) (r - 1);
                }
                al.add(c);
                if (r == 0) {
                    N--;
                }
                N /= 26;
            } N > 0 N 0 {
                long r = N % 26;
                char c = 'a';
                if (r == 0) {
                    c = 'z';
                } else {
                    c += (char) (r - 1);
                }
                al.add(c);
                if (r == 0) {
                    N--;
                }
                N /= 26;
            } long r = N % 26; r N % 26 N 26 char c = 'a'; c 'a' if (r == 0) {
                    c = 'z';
                } else {
                    c += (char) (r - 1);
                } r == 0 r 0 {
                    c = 'z';
                } c = 'z' c 'z' {
                    c += (char) (r - 1);
                } c += (char) (r - 1) c (char) (r - 1) r 1 al.add(c) al.add al c if (r == 0) {
                    N--;
                } r == 0 r 0 {
                    N--;
                } N-- N N /= 26 N 26 Collections.reverse(al) Collections.reverse Collections al for (Character c : al) {
                out.print(c);
            } Character c al {
                out.print(c);
            } {
                out.print(c);
            } out.print(c) out.print out c out.println() out.println out InputReader in in PrintWriter out out void debug(Object... os) {
            System.err.println(Arrays.deepToString(os));
        } debug {
            System.err.println(Arrays.deepToString(os));
        } System.err.println(Arrays.deepToString(os)) System.err.println System.err System System.err Arrays.deepToString(os) Arrays.deepToString Arrays os Object... os os static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }
    } InputReader BufferedReader reader; reader StringTokenizer tokenizer; tokenizer InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        } InputReader {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        } reader = new BufferedReader(new InputStreamReader(stream), 32768) reader new BufferedReader(new InputStreamReader(stream), 32768) tokenizer = null tokenizer null InputStream stream stream String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } next {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            } tokenizer == null || !tokenizer.hasMoreTokens() tokenizer == null tokenizer null !tokenizer.hasMoreTokens() tokenizer.hasMoreTokens() tokenizer.hasMoreTokens tokenizer {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            } try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                } IOException e {
                    throw new RuntimeException(e);
                } throw new RuntimeException(e); new RuntimeException(e) {
                    tokenizer = new StringTokenizer(reader.readLine());
                } tokenizer = new StringTokenizer(reader.readLine()) tokenizer new StringTokenizer(reader.readLine()) return tokenizer.nextToken(); tokenizer.nextToken() tokenizer.nextToken tokenizer int nextInt() {
            return Integer.parseInt(next());
        } nextInt {
            return Integer.parseInt(next());
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong() {
            return Long.parseLong(next());
        } nextLong {
            return Long.parseLong(next());
        } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public class Main {
    // static int INF = (1 << 30) - 1;
    // static long L_INF = (1L << 62) - 1;
    // static long MOD = (long) 1e9 + 7;

    static class Solver {
        long N;
        // int[] A;

        // write your code
        void solve(InputReader in, PrintWriter out) {
            N = in.nextLong();
            ArrayList<Character> al = new ArrayList<>();
            while (N > 0) {
                long r = N % 26;
                char c = 'a';
                if (r == 0) {
                    c = 'z';
                } else {
                    c += (char) (r - 1);
                }
                al.add(c);
                if (r == 0) {
                    N--;
                }
                N /= 26;
            }

            Collections.reverse(al);
            for (Character c : al) {
                out.print(c);
            }
            out.println();
        }

        void debug(Object... os) {
            System.err.println(Arrays.deepToString(os));
        }
    }

    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(in, out);
        out.close();
    }

    static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }
    }
} public class Main {
    // static int INF = (1 << 30) - 1;
    // static long L_INF = (1L << 62) - 1;
    // static long MOD = (long) 1e9 + 7;

    static class Solver {
        long N;
        // int[] A;

        // write your code
        void solve(InputReader in, PrintWriter out) {
            N = in.nextLong();
            ArrayList<Character> al = new ArrayList<>();
            while (N > 0) {
                long r = N % 26;
                char c = 'a';
                if (r == 0) {
                    c = 'z';
                } else {
                    c += (char) (r - 1);
                }
                al.add(c);
                if (r == 0) {
                    N--;
                }
                N /= 26;
            }

            Collections.reverse(al);
            for (Character c : al) {
                out.print(c);
            }
            out.println();
        }

        void debug(Object... os) {
            System.err.println(Arrays.deepToString(os));
        }
    }

    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(in, out);
        out.close();
    }

    static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }
    }
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.*;
import java.awt.Point;

public class Main {
    // static int INF = (1 << 30) - 1;
    // static long L_INF = (1L << 62) - 1;
    // static long MOD = (long) 1e9 + 7;

    static class Solver {
        long N;
        // int[] A;

        // write your code
        void solve(InputReader in, PrintWriter out) {
            N = in.nextLong();
            ArrayList<Character> al = new ArrayList<>();
            while (N > 0) {
                long r = N % 26;
                char c = 'a';
                if (r == 0) {
                    c = 'z';
                } else {
                    c += (char) (r - 1);
                }
                al.add(c);
                if (r == 0) {
                    N--;
                }
                N /= 26;
            }

            Collections.reverse(al);
            for (Character c : al) {
                out.print(c);
            }
            out.println();
        }

        void debug(Object... os) {
            System.err.println(Arrays.deepToString(os));
        }
    }

    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(in, out);
        out.close();
    }

    static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }
    }
}
