import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();

        String result = "";
        System.out.println(calc(result, N, 1));
        sc.close();

    }

    static String calc(String result, long N, int count) {
        if (N < 26) {
            return moji((int) N) + result;
        } else if (N == 26) {
            return moji(0) + result;
        }

        result = (moji((int) (N % 26))) + result;
        if (N % 26 != 0) {
            return calc(result, ((N - N % 26) / 26), count++);
        } else {
            return calc(result, ((N - 26) / 26), count++);
        }
    }

    static String moji(int N) {
        String moji = "";
        switch (N) {
            case 1:
                moji = "a";
                break;
            case 2:
                moji = "b";
                break;
            case 3:
                moji = "c";
                break;
            case 4:
                moji = "d";
                break;
            case 5:
                moji = "e";
                break;
            case 6:
                moji = "f";
                break;
            case 7:
                moji = "g";
                break;
            case 8:
                moji = "h";
                break;
            case 9:
                moji = "i";
                break;
            case 10:
                moji = "j";
                break;
            case 11:
                moji = "k";
                break;
            case 12:
                moji = "l";
                break;
            case 13:
                moji = "m";
                break;
            case 14:
                moji = "n";
                break;
            case 15:
                moji = "o";
                break;
            case 16:
                moji = "p";
                break;
            case 17:
                moji = "q";
                break;
            case 18:
                moji = "r";
                break;
            case 19:
                moji = "s";
                break;
            case 20:
                moji = "t";
                break;
            case 21:
                moji = "u";
                break;
            case 22:
                moji = "v";
                break;
            case 23:
                moji = "w";
                break;
            case 24:
                moji = "x";
                break;
            case 25:
                moji = "y";
                break;
            case 0:
                moji = "z";
                break;
        }
        return moji;
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();

        String result = "";
        System.out.println(calc(result, N, 1));
        sc.close();

    }

    static String calc(String result, long N, int count) {
        if (N < 26) {
            return moji((int) N) + result;
        } else if (N == 26) {
            return moji(0) + result;
        }

        result = (moji((int) (N % 26))) + result;
        if (N % 26 != 0) {
            return calc(result, ((N - N % 26) / 26), count++);
        } else {
            return calc(result, ((N - 26) / 26), count++);
        }
    }

    static String moji(int N) {
        String moji = "";
        switch (N) {
            case 1:
                moji = "a";
                break;
            case 2:
                moji = "b";
                break;
            case 3:
                moji = "c";
                break;
            case 4:
                moji = "d";
                break;
            case 5:
                moji = "e";
                break;
            case 6:
                moji = "f";
                break;
            case 7:
                moji = "g";
                break;
            case 8:
                moji = "h";
                break;
            case 9:
                moji = "i";
                break;
            case 10:
                moji = "j";
                break;
            case 11:
                moji = "k";
                break;
            case 12:
                moji = "l";
                break;
            case 13:
                moji = "m";
                break;
            case 14:
                moji = "n";
                break;
            case 15:
                moji = "o";
                break;
            case 16:
                moji = "p";
                break;
            case 17:
                moji = "q";
                break;
            case 18:
                moji = "r";
                break;
            case 19:
                moji = "s";
                break;
            case 20:
                moji = "t";
                break;
            case 21:
                moji = "u";
                break;
            case 22:
                moji = "v";
                break;
            case 23:
                moji = "w";
                break;
            case 24:
                moji = "x";
                break;
            case 25:
                moji = "y";
                break;
            case 0:
                moji = "z";
                break;
        }
        return moji;
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();

        String result = "";
        System.out.println(calc(result, N, 1));
        sc.close();

    } main {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();

        String result = "";
        System.out.println(calc(result, N, 1));
        sc.close();

    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long N = sc.nextLong(); N sc.nextLong() sc.nextLong sc String result = ""; result "" System.out.println(calc(result, N, 1)) System.out.println System.out System System.out calc(result, N, 1) calc result N 1 sc.close() sc.close sc String[] args args static String calc(String result, long N, int count) {
        if (N < 26) {
            return moji((int) N) + result;
        } else if (N == 26) {
            return moji(0) + result;
        }

        result = (moji((int) (N % 26))) + result;
        if (N % 26 != 0) {
            return calc(result, ((N - N % 26) / 26), count++);
        } else {
            return calc(result, ((N - 26) / 26), count++);
        }
    } calc {
        if (N < 26) {
            return moji((int) N) + result;
        } else if (N == 26) {
            return moji(0) + result;
        }

        result = (moji((int) (N % 26))) + result;
        if (N % 26 != 0) {
            return calc(result, ((N - N % 26) / 26), count++);
        } else {
            return calc(result, ((N - 26) / 26), count++);
        }
    } if (N < 26) {
            return moji((int) N) + result;
        } else if (N == 26) {
            return moji(0) + result;
        } N < 26 N 26 {
            return moji((int) N) + result;
        } return moji((int) N) + result; moji((int) N) + result moji((int) N) moji (int) N result if (N == 26) {
            return moji(0) + result;
        } N == 26 N 26 {
            return moji(0) + result;
        } return moji(0) + result; moji(0) + result moji(0) moji 0 result result = (moji((int) (N % 26))) + result result (moji((int) (N % 26))) + result (moji((int) (N % 26))) moji (int) (N % 26) N 26 result if (N % 26 != 0) {
            return calc(result, ((N - N % 26) / 26), count++);
        } else {
            return calc(result, ((N - 26) / 26), count++);
        } N % 26 != 0 N % 26 N 26 0 {
            return calc(result, ((N - N % 26) / 26), count++);
        } return calc(result, ((N - N % 26) / 26), count++); calc(result, ((N - N % 26) / 26), count++) calc result ((N - N % 26) / 26) (N - N % 26) N N % 26 N 26 26 count++ count {
            return calc(result, ((N - 26) / 26), count++);
        } return calc(result, ((N - 26) / 26), count++); calc(result, ((N - 26) / 26), count++) calc result ((N - 26) / 26) (N - 26) N 26 26 count++ count String result result long N N int count count static String moji(int N) {
        String moji = "";
        switch (N) {
            case 1:
                moji = "a";
                break;
            case 2:
                moji = "b";
                break;
            case 3:
                moji = "c";
                break;
            case 4:
                moji = "d";
                break;
            case 5:
                moji = "e";
                break;
            case 6:
                moji = "f";
                break;
            case 7:
                moji = "g";
                break;
            case 8:
                moji = "h";
                break;
            case 9:
                moji = "i";
                break;
            case 10:
                moji = "j";
                break;
            case 11:
                moji = "k";
                break;
            case 12:
                moji = "l";
                break;
            case 13:
                moji = "m";
                break;
            case 14:
                moji = "n";
                break;
            case 15:
                moji = "o";
                break;
            case 16:
                moji = "p";
                break;
            case 17:
                moji = "q";
                break;
            case 18:
                moji = "r";
                break;
            case 19:
                moji = "s";
                break;
            case 20:
                moji = "t";
                break;
            case 21:
                moji = "u";
                break;
            case 22:
                moji = "v";
                break;
            case 23:
                moji = "w";
                break;
            case 24:
                moji = "x";
                break;
            case 25:
                moji = "y";
                break;
            case 0:
                moji = "z";
                break;
        }
        return moji;
    } moji {
        String moji = "";
        switch (N) {
            case 1:
                moji = "a";
                break;
            case 2:
                moji = "b";
                break;
            case 3:
                moji = "c";
                break;
            case 4:
                moji = "d";
                break;
            case 5:
                moji = "e";
                break;
            case 6:
                moji = "f";
                break;
            case 7:
                moji = "g";
                break;
            case 8:
                moji = "h";
                break;
            case 9:
                moji = "i";
                break;
            case 10:
                moji = "j";
                break;
            case 11:
                moji = "k";
                break;
            case 12:
                moji = "l";
                break;
            case 13:
                moji = "m";
                break;
            case 14:
                moji = "n";
                break;
            case 15:
                moji = "o";
                break;
            case 16:
                moji = "p";
                break;
            case 17:
                moji = "q";
                break;
            case 18:
                moji = "r";
                break;
            case 19:
                moji = "s";
                break;
            case 20:
                moji = "t";
                break;
            case 21:
                moji = "u";
                break;
            case 22:
                moji = "v";
                break;
            case 23:
                moji = "w";
                break;
            case 24:
                moji = "x";
                break;
            case 25:
                moji = "y";
                break;
            case 0:
                moji = "z";
                break;
        }
        return moji;
    } String moji = ""; moji "" switch (N) {
            case 1:
                moji = "a";
                break;
            case 2:
                moji = "b";
                break;
            case 3:
                moji = "c";
                break;
            case 4:
                moji = "d";
                break;
            case 5:
                moji = "e";
                break;
            case 6:
                moji = "f";
                break;
            case 7:
                moji = "g";
                break;
            case 8:
                moji = "h";
                break;
            case 9:
                moji = "i";
                break;
            case 10:
                moji = "j";
                break;
            case 11:
                moji = "k";
                break;
            case 12:
                moji = "l";
                break;
            case 13:
                moji = "m";
                break;
            case 14:
                moji = "n";
                break;
            case 15:
                moji = "o";
                break;
            case 16:
                moji = "p";
                break;
            case 17:
                moji = "q";
                break;
            case 18:
                moji = "r";
                break;
            case 19:
                moji = "s";
                break;
            case 20:
                moji = "t";
                break;
            case 21:
                moji = "u";
                break;
            case 22:
                moji = "v";
                break;
            case 23:
                moji = "w";
                break;
            case 24:
                moji = "x";
                break;
            case 25:
                moji = "y";
                break;
            case 0:
                moji = "z";
                break;
        } N case 1: 1 case 1: moji = "a" moji "a" break; case 2: 2 case 2: moji = "b" moji "b" break; case 3: 3 case 3: moji = "c" moji "c" break; case 4: 4 case 4: moji = "d" moji "d" break; case 5: 5 case 5: moji = "e" moji "e" break; case 6: 6 case 6: moji = "f" moji "f" break; case 7: 7 case 7: moji = "g" moji "g" break; case 8: 8 case 8: moji = "h" moji "h" break; case 9: 9 case 9: moji = "i" moji "i" break; case 10: 10 case 10: moji = "j" moji "j" break; case 11: 11 case 11: moji = "k" moji "k" break; case 12: 12 case 12: moji = "l" moji "l" break; case 13: 13 case 13: moji = "m" moji "m" break; case 14: 14 case 14: moji = "n" moji "n" break; case 15: 15 case 15: moji = "o" moji "o" break; case 16: 16 case 16: moji = "p" moji "p" break; case 17: 17 case 17: moji = "q" moji "q" break; case 18: 18 case 18: moji = "r" moji "r" break; case 19: 19 case 19: moji = "s" moji "s" break; case 20: 20 case 20: moji = "t" moji "t" break; case 21: 21 case 21: moji = "u" moji "u" break; case 22: 22 case 22: moji = "v" moji "v" break; case 23: 23 case 23: moji = "w" moji "w" break; case 24: 24 case 24: moji = "x" moji "x" break; case 25: 25 case 25: moji = "y" moji "y" break; case 0: 0 case 0: moji = "z" moji "z" break; return moji; moji int N N public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();

        String result = "";
        System.out.println(calc(result, N, 1));
        sc.close();

    }

    static String calc(String result, long N, int count) {
        if (N < 26) {
            return moji((int) N) + result;
        } else if (N == 26) {
            return moji(0) + result;
        }

        result = (moji((int) (N % 26))) + result;
        if (N % 26 != 0) {
            return calc(result, ((N - N % 26) / 26), count++);
        } else {
            return calc(result, ((N - 26) / 26), count++);
        }
    }

    static String moji(int N) {
        String moji = "";
        switch (N) {
            case 1:
                moji = "a";
                break;
            case 2:
                moji = "b";
                break;
            case 3:
                moji = "c";
                break;
            case 4:
                moji = "d";
                break;
            case 5:
                moji = "e";
                break;
            case 6:
                moji = "f";
                break;
            case 7:
                moji = "g";
                break;
            case 8:
                moji = "h";
                break;
            case 9:
                moji = "i";
                break;
            case 10:
                moji = "j";
                break;
            case 11:
                moji = "k";
                break;
            case 12:
                moji = "l";
                break;
            case 13:
                moji = "m";
                break;
            case 14:
                moji = "n";
                break;
            case 15:
                moji = "o";
                break;
            case 16:
                moji = "p";
                break;
            case 17:
                moji = "q";
                break;
            case 18:
                moji = "r";
                break;
            case 19:
                moji = "s";
                break;
            case 20:
                moji = "t";
                break;
            case 21:
                moji = "u";
                break;
            case 22:
                moji = "v";
                break;
            case 23:
                moji = "w";
                break;
            case 24:
                moji = "x";
                break;
            case 25:
                moji = "y";
                break;
            case 0:
                moji = "z";
                break;
        }
        return moji;
    }
} public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();

        String result = "";
        System.out.println(calc(result, N, 1));
        sc.close();

    }

    static String calc(String result, long N, int count) {
        if (N < 26) {
            return moji((int) N) + result;
        } else if (N == 26) {
            return moji(0) + result;
        }

        result = (moji((int) (N % 26))) + result;
        if (N % 26 != 0) {
            return calc(result, ((N - N % 26) / 26), count++);
        } else {
            return calc(result, ((N - 26) / 26), count++);
        }
    }

    static String moji(int N) {
        String moji = "";
        switch (N) {
            case 1:
                moji = "a";
                break;
            case 2:
                moji = "b";
                break;
            case 3:
                moji = "c";
                break;
            case 4:
                moji = "d";
                break;
            case 5:
                moji = "e";
                break;
            case 6:
                moji = "f";
                break;
            case 7:
                moji = "g";
                break;
            case 8:
                moji = "h";
                break;
            case 9:
                moji = "i";
                break;
            case 10:
                moji = "j";
                break;
            case 11:
                moji = "k";
                break;
            case 12:
                moji = "l";
                break;
            case 13:
                moji = "m";
                break;
            case 14:
                moji = "n";
                break;
            case 15:
                moji = "o";
                break;
            case 16:
                moji = "p";
                break;
            case 17:
                moji = "q";
                break;
            case 18:
                moji = "r";
                break;
            case 19:
                moji = "s";
                break;
            case 20:
                moji = "t";
                break;
            case 21:
                moji = "u";
                break;
            case 22:
                moji = "v";
                break;
            case 23:
                moji = "w";
                break;
            case 24:
                moji = "x";
                break;
            case 25:
                moji = "y";
                break;
            case 0:
                moji = "z";
                break;
        }
        return moji;
    }
} Main
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();

        String result = "";
        System.out.println(calc(result, N, 1));
        sc.close();

    }

    static String calc(String result, long N, int count) {
        if (N < 26) {
            return moji((int) N) + result;
        } else if (N == 26) {
            return moji(0) + result;
        }

        result = (moji((int) (N % 26))) + result;
        if (N % 26 != 0) {
            return calc(result, ((N - N % 26) / 26), count++);
        } else {
            return calc(result, ((N - 26) / 26), count++);
        }
    }

    static String moji(int N) {
        String moji = "";
        switch (N) {
            case 1:
                moji = "a";
                break;
            case 2:
                moji = "b";
                break;
            case 3:
                moji = "c";
                break;
            case 4:
                moji = "d";
                break;
            case 5:
                moji = "e";
                break;
            case 6:
                moji = "f";
                break;
            case 7:
                moji = "g";
                break;
            case 8:
                moji = "h";
                break;
            case 9:
                moji = "i";
                break;
            case 10:
                moji = "j";
                break;
            case 11:
                moji = "k";
                break;
            case 12:
                moji = "l";
                break;
            case 13:
                moji = "m";
                break;
            case 14:
                moji = "n";
                break;
            case 15:
                moji = "o";
                break;
            case 16:
                moji = "p";
                break;
            case 17:
                moji = "q";
                break;
            case 18:
                moji = "r";
                break;
            case 19:
                moji = "s";
                break;
            case 20:
                moji = "t";
                break;
            case 21:
                moji = "u";
                break;
            case 22:
                moji = "v";
                break;
            case 23:
                moji = "w";
                break;
            case 24:
                moji = "x";
                break;
            case 25:
                moji = "y";
                break;
            case 0:
                moji = "z";
                break;
        }
        return moji;
    }
}
