import java.util.HashMap;
import java.util.Scanner;

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

                long N = scan.nextLong();

                HashMap<Long, String> alphabetHash = new HashMap<Long, String>();
                alphabetHash.put((long)0, "a");
                alphabetHash.put((long)1, "b");
                alphabetHash.put((long)2, "c");
                alphabetHash.put((long)3, "d");
                alphabetHash.put((long)4, "e");
                alphabetHash.put((long)5, "f");
                alphabetHash.put((long)6, "g");
                alphabetHash.put((long)7, "h");
                alphabetHash.put((long)8, "i");
                alphabetHash.put((long)9, "j");
                alphabetHash.put((long)10, "k");
                alphabetHash.put((long)11, "l");
                alphabetHash.put((long)12, "m");
                alphabetHash.put((long)13, "n");
                alphabetHash.put((long)14, "o");
                alphabetHash.put((long)15, "p");
                alphabetHash.put((long)16, "q");
                alphabetHash.put((long)17, "r");
                alphabetHash.put((long)18, "s");
                alphabetHash.put((long)19, "t");
                alphabetHash.put((long)20, "u");
                alphabetHash.put((long)21, "v");
                alphabetHash.put((long)22, "w");
                alphabetHash.put((long)23, "x");
                alphabetHash.put((long)24, "y");
                alphabetHash.put((long)25, "z");


                long len = 1;

                while (N - Math.pow(26, len) > 0) {
                	N -= Math.pow((long)26, len);
                	len++;
                }

                N--;

                while (len > 0) {
                	long temp = N/(long)Math.pow(26, len-1);
                	System.out.print(alphabetHash.get(temp));
                	N %= Math.pow(26, len-1);
                	len--;
                }

                System.out.println();

                scan.close();

        }

} import java.util.HashMap; HashMap java.util import java.util.Scanner; Scanner java.util public class Main {
        public static void main(String[] args) {
                Scanner scan = new Scanner(System.in);

                long N = scan.nextLong();

                HashMap<Long, String> alphabetHash = new HashMap<Long, String>();
                alphabetHash.put((long)0, "a");
                alphabetHash.put((long)1, "b");
                alphabetHash.put((long)2, "c");
                alphabetHash.put((long)3, "d");
                alphabetHash.put((long)4, "e");
                alphabetHash.put((long)5, "f");
                alphabetHash.put((long)6, "g");
                alphabetHash.put((long)7, "h");
                alphabetHash.put((long)8, "i");
                alphabetHash.put((long)9, "j");
                alphabetHash.put((long)10, "k");
                alphabetHash.put((long)11, "l");
                alphabetHash.put((long)12, "m");
                alphabetHash.put((long)13, "n");
                alphabetHash.put((long)14, "o");
                alphabetHash.put((long)15, "p");
                alphabetHash.put((long)16, "q");
                alphabetHash.put((long)17, "r");
                alphabetHash.put((long)18, "s");
                alphabetHash.put((long)19, "t");
                alphabetHash.put((long)20, "u");
                alphabetHash.put((long)21, "v");
                alphabetHash.put((long)22, "w");
                alphabetHash.put((long)23, "x");
                alphabetHash.put((long)24, "y");
                alphabetHash.put((long)25, "z");


                long len = 1;

                while (N - Math.pow(26, len) > 0) {
                	N -= Math.pow((long)26, len);
                	len++;
                }

                N--;

                while (len > 0) {
                	long temp = N/(long)Math.pow(26, len-1);
                	System.out.print(alphabetHash.get(temp));
                	N %= Math.pow(26, len-1);
                	len--;
                }

                System.out.println();

                scan.close();

        }

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

                long N = scan.nextLong();

                HashMap<Long, String> alphabetHash = new HashMap<Long, String>();
                alphabetHash.put((long)0, "a");
                alphabetHash.put((long)1, "b");
                alphabetHash.put((long)2, "c");
                alphabetHash.put((long)3, "d");
                alphabetHash.put((long)4, "e");
                alphabetHash.put((long)5, "f");
                alphabetHash.put((long)6, "g");
                alphabetHash.put((long)7, "h");
                alphabetHash.put((long)8, "i");
                alphabetHash.put((long)9, "j");
                alphabetHash.put((long)10, "k");
                alphabetHash.put((long)11, "l");
                alphabetHash.put((long)12, "m");
                alphabetHash.put((long)13, "n");
                alphabetHash.put((long)14, "o");
                alphabetHash.put((long)15, "p");
                alphabetHash.put((long)16, "q");
                alphabetHash.put((long)17, "r");
                alphabetHash.put((long)18, "s");
                alphabetHash.put((long)19, "t");
                alphabetHash.put((long)20, "u");
                alphabetHash.put((long)21, "v");
                alphabetHash.put((long)22, "w");
                alphabetHash.put((long)23, "x");
                alphabetHash.put((long)24, "y");
                alphabetHash.put((long)25, "z");


                long len = 1;

                while (N - Math.pow(26, len) > 0) {
                	N -= Math.pow((long)26, len);
                	len++;
                }

                N--;

                while (len > 0) {
                	long temp = N/(long)Math.pow(26, len-1);
                	System.out.print(alphabetHash.get(temp));
                	N %= Math.pow(26, len-1);
                	len--;
                }

                System.out.println();

                scan.close();

        } main {
                Scanner scan = new Scanner(System.in);

                long N = scan.nextLong();

                HashMap<Long, String> alphabetHash = new HashMap<Long, String>();
                alphabetHash.put((long)0, "a");
                alphabetHash.put((long)1, "b");
                alphabetHash.put((long)2, "c");
                alphabetHash.put((long)3, "d");
                alphabetHash.put((long)4, "e");
                alphabetHash.put((long)5, "f");
                alphabetHash.put((long)6, "g");
                alphabetHash.put((long)7, "h");
                alphabetHash.put((long)8, "i");
                alphabetHash.put((long)9, "j");
                alphabetHash.put((long)10, "k");
                alphabetHash.put((long)11, "l");
                alphabetHash.put((long)12, "m");
                alphabetHash.put((long)13, "n");
                alphabetHash.put((long)14, "o");
                alphabetHash.put((long)15, "p");
                alphabetHash.put((long)16, "q");
                alphabetHash.put((long)17, "r");
                alphabetHash.put((long)18, "s");
                alphabetHash.put((long)19, "t");
                alphabetHash.put((long)20, "u");
                alphabetHash.put((long)21, "v");
                alphabetHash.put((long)22, "w");
                alphabetHash.put((long)23, "x");
                alphabetHash.put((long)24, "y");
                alphabetHash.put((long)25, "z");


                long len = 1;

                while (N - Math.pow(26, len) > 0) {
                	N -= Math.pow((long)26, len);
                	len++;
                }

                N--;

                while (len > 0) {
                	long temp = N/(long)Math.pow(26, len-1);
                	System.out.print(alphabetHash.get(temp));
                	N %= Math.pow(26, len-1);
                	len--;
                }

                System.out.println();

                scan.close();

        } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) long N = scan.nextLong(); N scan.nextLong() scan.nextLong scan HashMap<Long, String> alphabetHash = new HashMap<Long, String>(); alphabetHash new HashMap<Long, String>() alphabetHash.put((long)0, "a") alphabetHash.put alphabetHash (long)0 "a" alphabetHash.put((long)1, "b") alphabetHash.put alphabetHash (long)1 "b" alphabetHash.put((long)2, "c") alphabetHash.put alphabetHash (long)2 "c" alphabetHash.put((long)3, "d") alphabetHash.put alphabetHash (long)3 "d" alphabetHash.put((long)4, "e") alphabetHash.put alphabetHash (long)4 "e" alphabetHash.put((long)5, "f") alphabetHash.put alphabetHash (long)5 "f" alphabetHash.put((long)6, "g") alphabetHash.put alphabetHash (long)6 "g" alphabetHash.put((long)7, "h") alphabetHash.put alphabetHash (long)7 "h" alphabetHash.put((long)8, "i") alphabetHash.put alphabetHash (long)8 "i" alphabetHash.put((long)9, "j") alphabetHash.put alphabetHash (long)9 "j" alphabetHash.put((long)10, "k") alphabetHash.put alphabetHash (long)10 "k" alphabetHash.put((long)11, "l") alphabetHash.put alphabetHash (long)11 "l" alphabetHash.put((long)12, "m") alphabetHash.put alphabetHash (long)12 "m" alphabetHash.put((long)13, "n") alphabetHash.put alphabetHash (long)13 "n" alphabetHash.put((long)14, "o") alphabetHash.put alphabetHash (long)14 "o" alphabetHash.put((long)15, "p") alphabetHash.put alphabetHash (long)15 "p" alphabetHash.put((long)16, "q") alphabetHash.put alphabetHash (long)16 "q" alphabetHash.put((long)17, "r") alphabetHash.put alphabetHash (long)17 "r" alphabetHash.put((long)18, "s") alphabetHash.put alphabetHash (long)18 "s" alphabetHash.put((long)19, "t") alphabetHash.put alphabetHash (long)19 "t" alphabetHash.put((long)20, "u") alphabetHash.put alphabetHash (long)20 "u" alphabetHash.put((long)21, "v") alphabetHash.put alphabetHash (long)21 "v" alphabetHash.put((long)22, "w") alphabetHash.put alphabetHash (long)22 "w" alphabetHash.put((long)23, "x") alphabetHash.put alphabetHash (long)23 "x" alphabetHash.put((long)24, "y") alphabetHash.put alphabetHash (long)24 "y" alphabetHash.put((long)25, "z") alphabetHash.put alphabetHash (long)25 "z" long len = 1; len 1 while (N - Math.pow(26, len) > 0) {
                	N -= Math.pow((long)26, len);
                	len++;
                } N - Math.pow(26, len) > 0 N - Math.pow(26, len) N Math.pow(26, len) Math.pow Math 26 len 0 {
                	N -= Math.pow((long)26, len);
                	len++;
                } N -= Math.pow((long)26, len) N Math.pow((long)26, len) Math.pow Math (long)26 len len++ len N-- N while (len > 0) {
                	long temp = N/(long)Math.pow(26, len-1);
                	System.out.print(alphabetHash.get(temp));
                	N %= Math.pow(26, len-1);
                	len--;
                } len > 0 len 0 {
                	long temp = N/(long)Math.pow(26, len-1);
                	System.out.print(alphabetHash.get(temp));
                	N %= Math.pow(26, len-1);
                	len--;
                } long temp = N/(long)Math.pow(26, len-1); temp N/(long)Math.pow(26, len-1) N (long)Math.pow(26, len-1) Math.pow Math 26 len-1 len 1 System.out.print(alphabetHash.get(temp)) System.out.print System.out System System.out alphabetHash.get(temp) alphabetHash.get alphabetHash temp N %= Math.pow(26, len-1) N Math.pow(26, len-1) Math.pow Math 26 len-1 len 1 len-- len System.out.println() System.out.println System.out System System.out scan.close() scan.close scan String[] args args public class Main {
        public static void main(String[] args) {
                Scanner scan = new Scanner(System.in);

                long N = scan.nextLong();

                HashMap<Long, String> alphabetHash = new HashMap<Long, String>();
                alphabetHash.put((long)0, "a");
                alphabetHash.put((long)1, "b");
                alphabetHash.put((long)2, "c");
                alphabetHash.put((long)3, "d");
                alphabetHash.put((long)4, "e");
                alphabetHash.put((long)5, "f");
                alphabetHash.put((long)6, "g");
                alphabetHash.put((long)7, "h");
                alphabetHash.put((long)8, "i");
                alphabetHash.put((long)9, "j");
                alphabetHash.put((long)10, "k");
                alphabetHash.put((long)11, "l");
                alphabetHash.put((long)12, "m");
                alphabetHash.put((long)13, "n");
                alphabetHash.put((long)14, "o");
                alphabetHash.put((long)15, "p");
                alphabetHash.put((long)16, "q");
                alphabetHash.put((long)17, "r");
                alphabetHash.put((long)18, "s");
                alphabetHash.put((long)19, "t");
                alphabetHash.put((long)20, "u");
                alphabetHash.put((long)21, "v");
                alphabetHash.put((long)22, "w");
                alphabetHash.put((long)23, "x");
                alphabetHash.put((long)24, "y");
                alphabetHash.put((long)25, "z");


                long len = 1;

                while (N - Math.pow(26, len) > 0) {
                	N -= Math.pow((long)26, len);
                	len++;
                }

                N--;

                while (len > 0) {
                	long temp = N/(long)Math.pow(26, len-1);
                	System.out.print(alphabetHash.get(temp));
                	N %= Math.pow(26, len-1);
                	len--;
                }

                System.out.println();

                scan.close();

        }

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

                long N = scan.nextLong();

                HashMap<Long, String> alphabetHash = new HashMap<Long, String>();
                alphabetHash.put((long)0, "a");
                alphabetHash.put((long)1, "b");
                alphabetHash.put((long)2, "c");
                alphabetHash.put((long)3, "d");
                alphabetHash.put((long)4, "e");
                alphabetHash.put((long)5, "f");
                alphabetHash.put((long)6, "g");
                alphabetHash.put((long)7, "h");
                alphabetHash.put((long)8, "i");
                alphabetHash.put((long)9, "j");
                alphabetHash.put((long)10, "k");
                alphabetHash.put((long)11, "l");
                alphabetHash.put((long)12, "m");
                alphabetHash.put((long)13, "n");
                alphabetHash.put((long)14, "o");
                alphabetHash.put((long)15, "p");
                alphabetHash.put((long)16, "q");
                alphabetHash.put((long)17, "r");
                alphabetHash.put((long)18, "s");
                alphabetHash.put((long)19, "t");
                alphabetHash.put((long)20, "u");
                alphabetHash.put((long)21, "v");
                alphabetHash.put((long)22, "w");
                alphabetHash.put((long)23, "x");
                alphabetHash.put((long)24, "y");
                alphabetHash.put((long)25, "z");


                long len = 1;

                while (N - Math.pow(26, len) > 0) {
                	N -= Math.pow((long)26, len);
                	len++;
                }

                N--;

                while (len > 0) {
                	long temp = N/(long)Math.pow(26, len-1);
                	System.out.print(alphabetHash.get(temp));
                	N %= Math.pow(26, len-1);
                	len--;
                }

                System.out.println();

                scan.close();

        }

} Main
import java.util.HashMap;
import java.util.Scanner;

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

                long N = scan.nextLong();

                HashMap<Long, String> alphabetHash = new HashMap<Long, String>();
                alphabetHash.put((long)0, "a");
                alphabetHash.put((long)1, "b");
                alphabetHash.put((long)2, "c");
                alphabetHash.put((long)3, "d");
                alphabetHash.put((long)4, "e");
                alphabetHash.put((long)5, "f");
                alphabetHash.put((long)6, "g");
                alphabetHash.put((long)7, "h");
                alphabetHash.put((long)8, "i");
                alphabetHash.put((long)9, "j");
                alphabetHash.put((long)10, "k");
                alphabetHash.put((long)11, "l");
                alphabetHash.put((long)12, "m");
                alphabetHash.put((long)13, "n");
                alphabetHash.put((long)14, "o");
                alphabetHash.put((long)15, "p");
                alphabetHash.put((long)16, "q");
                alphabetHash.put((long)17, "r");
                alphabetHash.put((long)18, "s");
                alphabetHash.put((long)19, "t");
                alphabetHash.put((long)20, "u");
                alphabetHash.put((long)21, "v");
                alphabetHash.put((long)22, "w");
                alphabetHash.put((long)23, "x");
                alphabetHash.put((long)24, "y");
                alphabetHash.put((long)25, "z");


                long len = 1;

                while (N - Math.pow(26, len) > 0) {
                	N -= Math.pow((long)26, len);
                	len++;
                }

                N--;

                while (len > 0) {
                	long temp = N/(long)Math.pow(26, len-1);
                	System.out.print(alphabetHash.get(temp));
                	N %= Math.pow(26, len-1);
                	len--;
                }

                System.out.println();

                scan.close();

        }

}