import java.util.Scanner;
public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        long x = in.nextLong();
        System.out.println(asd(x - 1));
    }

    public static String asd(long i) {
        if (i < 0) {
            return "-" + asd(-i - 1);
        }

        long quot = i / 26;
        long rem = i % 26;
        char letter = (char) ((int) 'a' + rem);
        if (quot == 0) {
            return "" + letter;
        } else {
            return asd(quot - 1) + letter;
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        long x = in.nextLong();
        System.out.println(asd(x - 1));
    }

    public static String asd(long i) {
        if (i < 0) {
            return "-" + asd(-i - 1);
        }

        long quot = i / 26;
        long rem = i % 26;
        char letter = (char) ((int) 'a' + rem);
        if (quot == 0) {
            return "" + letter;
        } else {
            return asd(quot - 1) + letter;
        }
    }
} Main public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        long x = in.nextLong();
        System.out.println(asd(x - 1));
    } main {
        Scanner in = new Scanner(System.in);
        long x = in.nextLong();
        System.out.println(asd(x - 1));
    } Scanner in = new Scanner(System.in); in new Scanner(System.in) long x = in.nextLong(); x in.nextLong() in.nextLong in System.out.println(asd(x - 1)) System.out.println System.out System System.out asd(x - 1) asd x - 1 x 1 String[] args args public static String asd(long i) {
        if (i < 0) {
            return "-" + asd(-i - 1);
        }

        long quot = i / 26;
        long rem = i % 26;
        char letter = (char) ((int) 'a' + rem);
        if (quot == 0) {
            return "" + letter;
        } else {
            return asd(quot - 1) + letter;
        }
    } asd {
        if (i < 0) {
            return "-" + asd(-i - 1);
        }

        long quot = i / 26;
        long rem = i % 26;
        char letter = (char) ((int) 'a' + rem);
        if (quot == 0) {
            return "" + letter;
        } else {
            return asd(quot - 1) + letter;
        }
    } if (i < 0) {
            return "-" + asd(-i - 1);
        } i < 0 i 0 {
            return "-" + asd(-i - 1);
        } return "-" + asd(-i - 1); "-" + asd(-i - 1) "-" asd(-i - 1) asd -i - 1 -i i 1 long quot = i / 26; quot i / 26 i 26 long rem = i % 26; rem i % 26 i 26 char letter = (char) ((int) 'a' + rem); letter (char) ((int) 'a' + rem) (int) 'a' rem if (quot == 0) {
            return "" + letter;
        } else {
            return asd(quot - 1) + letter;
        } quot == 0 quot 0 {
            return "" + letter;
        } return "" + letter; "" + letter "" letter {
            return asd(quot - 1) + letter;
        } return asd(quot - 1) + letter; asd(quot - 1) + letter asd(quot - 1) asd quot - 1 quot 1 letter long i i public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        long x = in.nextLong();
        System.out.println(asd(x - 1));
    }

    public static String asd(long i) {
        if (i < 0) {
            return "-" + asd(-i - 1);
        }

        long quot = i / 26;
        long rem = i % 26;
        char letter = (char) ((int) 'a' + rem);
        if (quot == 0) {
            return "" + letter;
        } else {
            return asd(quot - 1) + letter;
        }
    }
} public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        long x = in.nextLong();
        System.out.println(asd(x - 1));
    }

    public static String asd(long i) {
        if (i < 0) {
            return "-" + asd(-i - 1);
        }

        long quot = i / 26;
        long rem = i % 26;
        char letter = (char) ((int) 'a' + rem);
        if (quot == 0) {
            return "" + letter;
        } else {
            return asd(quot - 1) + letter;
        }
    }
} Main
import java.util.Scanner;
public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        long x = in.nextLong();
        System.out.println(asd(x - 1));
    }

    public static String asd(long i) {
        if (i < 0) {
            return "-" + asd(-i - 1);
        }

        long quot = i / 26;
        long rem = i % 26;
        char letter = (char) ((int) 'a' + rem);
        if (quot == 0) {
            return "" + letter;
        } else {
            return asd(quot - 1) + letter;
        }
    }
}
