Measuring time interval

Im given this code to test time interval:

import time
start = time.time()
# The program you want to test
end = time.time()
time_interval = end – start

My program:

number=int(input("Please enter a number:"))
if number<2:
    print("The number",number,"is not prime number.")
else:
    for x in range (2,int((number/2)+1)):
        if number%x==0:
            print("The number",number,"is not prime number.")
            break
    else:
        print("The number",number,"is a prime number.")

Final code:

import time
start=time.time()
number=int(input("Please enter a number:"))
if number<2:
    print("The number",number,"is not prime number.")
else:
    for x in range (2,int((number/2)+1)):
        if number%x==0:
            print("The number",number,"is not prime number.")
            break
    else:
        print("The number",number,"is a prime number.")

end=time.time()
time_interval=end-start

My problem is that it runs my program and stops, it doesnt tell me the time interval, why is this occuring?