with open('INPUT.TXT') as file:
read_file = file.readline().strip()
if read_file[3] == '=':
if read_file[1] == '+':
number_x = int(read_file[-1]) - int(read_file[2])
elif read_file[1] == "-":
number_x = int(read_file[0]) - int(read_file[-1])
with open('OUTPUT.TXT', 'w') as write_file:
write_file.write(str(number_x))