Where to put Error? ValueError?

Question

I try to put except for "x" and "y", i think it should be a ValueError, cose i want my program to run, print: "it can't be a string it have to be integer" and ask again for first number. My code is:

import time
print("hello")
time.sleep(5)

x=int(input("first number: ")
y=int(input("second number")
print(x+y)

if x+y <= 20:
print("not bad")
elif x+y >= 21:
print("good")

time.sleep(3)
print("goodbye")

I tried to put "try:", "except ValueError:", "print("it can't be a string it have to be integer" everywhere but it doesn't work...

Answer 1

while True:
try:
a=int(input())
break
except ValueError:
print("it can't be a string ,it has to be am integer")

print(a)

Input
"6"
5

works fine and prints it can't be a string and then the correct output

Answer 2

Done! thank You:)