Python Calculator

'''
Simple calculator in Python
Coded by Donny
'''
def ans(x):
    print("The answer is : ",x,"\n")
def add(x, y):
    sum = x + y
    ans(sum)
def sub(x, y):
    min = x - y
    ans(min)
def div(x, y):
    divis = x / y
    ans(divis)
def mul(x, y):
    mult = x * y
    ans(mult)

usrin = input(">>>  ")

divide = usrin.split(' ')
first = divide[0]
op = divide[1]
second = divide[2]

if not first:
    print("The first number should not be left blank!")
    exit
elif not second:
    print("The second number should not be left blank!")
    exit
elif not op:
    print("The operator should not be left blank!")

first = int(first)
second = int(second)

if op == '+':
    add(first, second)
elif op == '-':
    sub(first, second)
elif op == '/':
    div(first, second)
elif op == '*':
    mul(first, second)
else:
    print("ERROR! Invalid OP!")