def binary_operator(n1, n2, o):
    if o == '+':
        out = bin(int(n1, 2) + int(n2, 2))[2:]
        return '0' * (16 - len(out)) + out
    elif o == '-':
        out = bin(abs(int(n1, 2) - int(n2, 2)))[2:]
        return '1' + '0' * (15 - len(out)) + out if (int(n1, 2) - int(n2, 2)) < 0 else '0' * (16 - len(out)) + out