import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Stack;
import java.util.StringTokenizer;

public class Main {
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();

        long n = sc.nextLong();

        Stack<Character> stack = new Stack<>();
        while (n > 26) {
            int t = (int)(n % 26);
            if (t == 0) {
                t = 26;
                n -= 26;
            }

            char c = (char)('a' + t - 1);
            //System.out.println(c);
            stack.push(c);
            //n -= 26;
            n /= 26;
        }
        //System.out.println((char)('a' + n - 1));
        stack.push((char)('a' + n - 1));

        PrintWriter pw = new PrintWriter(System.out);
        while (!stack.empty()) {
            pw.print(stack.pop());
        }

        pw.println();
        pw.flush();
    }

    static class MyScanner {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in), 1 << 15);
        StringTokenizer tokenizer;

        String next() {
            try {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
            } catch (IOException ignored) {
            }
            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.InputStreamReader; InputStreamReader java.io import java.io.PrintWriter; PrintWriter java.io import java.util.Stack; Stack java.util import java.util.StringTokenizer; StringTokenizer java.util public class Main {
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();

        long n = sc.nextLong();

        Stack<Character> stack = new Stack<>();
        while (n > 26) {
            int t = (int)(n % 26);
            if (t == 0) {
                t = 26;
                n -= 26;
            }

            char c = (char)('a' + t - 1);
            //System.out.println(c);
            stack.push(c);
            //n -= 26;
            n /= 26;
        }
        //System.out.println((char)('a' + n - 1));
        stack.push((char)('a' + n - 1));

        PrintWriter pw = new PrintWriter(System.out);
        while (!stack.empty()) {
            pw.print(stack.pop());
        }

        pw.println();
        pw.flush();
    }

    static class MyScanner {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in), 1 << 15);
        StringTokenizer tokenizer;

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

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

        long nextLong() {
            return Long.parseLong(next());
        }
    }
} Main public static void main(String[] args) {
        MyScanner sc = new MyScanner();

        long n = sc.nextLong();

        Stack<Character> stack = new Stack<>();
        while (n > 26) {
            int t = (int)(n % 26);
            if (t == 0) {
                t = 26;
                n -= 26;
            }

            char c = (char)('a' + t - 1);
            //System.out.println(c);
            stack.push(c);
            //n -= 26;
            n /= 26;
        }
        //System.out.println((char)('a' + n - 1));
        stack.push((char)('a' + n - 1));

        PrintWriter pw = new PrintWriter(System.out);
        while (!stack.empty()) {
            pw.print(stack.pop());
        }

        pw.println();
        pw.flush();
    } main {
        MyScanner sc = new MyScanner();

        long n = sc.nextLong();

        Stack<Character> stack = new Stack<>();
        while (n > 26) {
            int t = (int)(n % 26);
            if (t == 0) {
                t = 26;
                n -= 26;
            }

            char c = (char)('a' + t - 1);
            //System.out.println(c);
            stack.push(c);
            //n -= 26;
            n /= 26;
        }
        //System.out.println((char)('a' + n - 1));
        stack.push((char)('a' + n - 1));

        PrintWriter pw = new PrintWriter(System.out);
        while (!stack.empty()) {
            pw.print(stack.pop());
        }

        pw.println();
        pw.flush();
    } MyScanner sc = new MyScanner(); sc new MyScanner() long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc Stack<Character> stack = new Stack<>(); stack new Stack<>() while (n > 26) {
            int t = (int)(n % 26);
            if (t == 0) {
                t = 26;
                n -= 26;
            }

            char c = (char)('a' + t - 1);
            //System.out.println(c);
            stack.push(c);
            //n -= 26;
            n /= 26;
        } n > 26 n 26 {
            int t = (int)(n % 26);
            if (t == 0) {
                t = 26;
                n -= 26;
            }

            char c = (char)('a' + t - 1);
            //System.out.println(c);
            stack.push(c);
            //n -= 26;
            n /= 26;
        } int t = (int)(n % 26); t (int)(n % 26) n 26 if (t == 0) {
                t = 26;
                n -= 26;
            } t == 0 t 0 {
                t = 26;
                n -= 26;
            } t = 26 t 26 n -= 26 n 26 char c = (char)('a' + t - 1); c (char)('a' + t - 1) 'a' + t 'a' t 1 stack.push(c) stack.push stack c n /= 26 n 26 stack.push((char)('a' + n - 1)) stack.push stack (char)('a' + n - 1) 'a' + n 'a' n 1 PrintWriter pw = new PrintWriter(System.out); pw new PrintWriter(System.out) while (!stack.empty()) {
            pw.print(stack.pop());
        } !stack.empty() stack.empty() stack.empty stack {
            pw.print(stack.pop());
        } pw.print(stack.pop()) pw.print pw stack.pop() stack.pop stack pw.println() pw.println pw pw.flush() pw.flush pw String[] args args static class MyScanner {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in), 1 << 15);
        StringTokenizer tokenizer;

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

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

        long nextLong() {
            return Long.parseLong(next());
        }
    } MyScanner BufferedReader reader = new BufferedReader(new InputStreamReader(System.in), 1 << 15); reader new BufferedReader(new InputStreamReader(System.in), 1 << 15) StringTokenizer tokenizer; tokenizer String next() {
            try {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
            } catch (IOException ignored) {
            }
            return tokenizer.nextToken();
        } next {
            try {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
            } catch (IOException ignored) {
            }
            return tokenizer.nextToken();
        } try {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
            } catch (IOException ignored) {
            } catch (IOException ignored) {
            } IOException ignored {
            } {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
            } while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                } tokenizer == null || !tokenizer.hasMoreTokens() tokenizer == null tokenizer null !tokenizer.hasMoreTokens() tokenizer.hasMoreTokens() tokenizer.hasMoreTokens tokenizer {
                    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 {
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();

        long n = sc.nextLong();

        Stack<Character> stack = new Stack<>();
        while (n > 26) {
            int t = (int)(n % 26);
            if (t == 0) {
                t = 26;
                n -= 26;
            }

            char c = (char)('a' + t - 1);
            //System.out.println(c);
            stack.push(c);
            //n -= 26;
            n /= 26;
        }
        //System.out.println((char)('a' + n - 1));
        stack.push((char)('a' + n - 1));

        PrintWriter pw = new PrintWriter(System.out);
        while (!stack.empty()) {
            pw.print(stack.pop());
        }

        pw.println();
        pw.flush();
    }

    static class MyScanner {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in), 1 << 15);
        StringTokenizer tokenizer;

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

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

        long nextLong() {
            return Long.parseLong(next());
        }
    }
} public class Main {
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();

        long n = sc.nextLong();

        Stack<Character> stack = new Stack<>();
        while (n > 26) {
            int t = (int)(n % 26);
            if (t == 0) {
                t = 26;
                n -= 26;
            }

            char c = (char)('a' + t - 1);
            //System.out.println(c);
            stack.push(c);
            //n -= 26;
            n /= 26;
        }
        //System.out.println((char)('a' + n - 1));
        stack.push((char)('a' + n - 1));

        PrintWriter pw = new PrintWriter(System.out);
        while (!stack.empty()) {
            pw.print(stack.pop());
        }

        pw.println();
        pw.flush();
    }

    static class MyScanner {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in), 1 << 15);
        StringTokenizer tokenizer;

        String next() {
            try {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
            } catch (IOException ignored) {
            }
            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.InputStreamReader;
import java.io.PrintWriter;
import java.util.Stack;
import java.util.StringTokenizer;

public class Main {
    public static void main(String[] args) {
        MyScanner sc = new MyScanner();

        long n = sc.nextLong();

        Stack<Character> stack = new Stack<>();
        while (n > 26) {
            int t = (int)(n % 26);
            if (t == 0) {
                t = 26;
                n -= 26;
            }

            char c = (char)('a' + t - 1);
            //System.out.println(c);
            stack.push(c);
            //n -= 26;
            n /= 26;
        }
        //System.out.println((char)('a' + n - 1));
        stack.push((char)('a' + n - 1));

        PrintWriter pw = new PrintWriter(System.out);
        while (!stack.empty()) {
            pw.print(stack.pop());
        }

        pw.println();
        pw.flush();
    }

    static class MyScanner {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in), 1 << 15);
        StringTokenizer tokenizer;

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

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

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