# put your python code here
first_num = float(input())
second_num = float(input())
operation = input()
if operation == 'mod':
if second_num == 0:
print("Деление на 0!")
elif operation == '-':
print(first_num - second_num)
elif operation == '+':
print(first_num + second_num)
elif operation == '*':
print(first_num * second_num)
elif operation == '/':
print(first_num / second_num)
else:
print("")
