Syntax error in else statement

Question

#Calculator in python

#this function adds two numbers.
def add(x, y):
return x + y

#this function subtracts two numbers.
def subtract(x, y):
return x - y

#this function multiplies two numbers.
def multiply(x, y):
return x * y

#this function divides two numbers.
def divide(x, y):
return x / y

print("select opration")
print("1. Add")
print("2. Subtract")
print("3. Multiply")
print("4. Divide")

#take choice from the user
while true:
choice = input("enter choice(1/2/3/4)")

#check if the choice is one of the four options
if choice in('1','2','3','4'):
num1 = float(input("enter first number: "))
num2 = float(input("enter second number: "))

if choice == 1:
print("num1", "+", "num2", "=", add(num1, num2))

elif choice == 2:
print("num1", "-", "num2", "=", subtract(num1, num2))

elif choice == 3:
print("num1", "*", "num2", "=", multiply(num1, num2))

elif choice == 4:
print("num1", "/", "num2", "=", divide(num1, num2))
break

else:
print("invalid input")

view code: https://code.sololearn.com/cdpgz7ZT9wbU/#py

#When I run it, it keeps giving syntax error.