def main(a):
    numbers = {
        10: "A",
        11: "B",
        12: "C",
        13: "D",
        14: "E",
        15: "F"
    }
    if a >= 0:
        return hex(a)[2:].upper()
    else:
        answer_bin = bin(abs(a))[2:]
        if len(answer_bin) % 8 != 0:
            answer_bin = "0" * (8 - len(answer_bin) % 8) + answer_bin
        answer_bin_inversed = ""
        for i in answer_bin:
            answer_bin_inversed += str((int(i) + 1) % 2)
        return hex(int(answer_bin_inversed, 2) + 1)[2:].upper()

print(main(-1))