How to get the the "Error" message printed in this situation because the "else" statement doesn't work?

Write the program that reads in input three integers a, b and c. If the integer c is equal to 1, then the program displays on output (prints) the value of a + b; if c is 2 then the program displays the value of a-b; if c is equal to 3 then the output will be the value of ab. Finally, if the value 4 is assigned to c, then the program displays the value of a^2 + ba. If c contains another value, the program displays the message "Error"

a = int(input())

b = int(input())

c = int(input())

if c == 1 :

print(a + b)

if c == 2 :

print(a - b)

if c == 3 :

print(a * b)

if c == 4 :

print(a**2 + b*a)

else :

print('Error')