Check if a number is prime

num = int(input("Enter an integer:"))
count = 0
for i in range(1,num+1):
    if num%i == 0:
        count+=1
if count == 2:
    print(num,"is a prime number.")
elif num == 1:
    print("1 is neither prime nor composite.")
elif num<0:
    print("Numbers less than zero are negative which cannot be prime numbers.")
elif count>2:
    print(num,"is a composite number.")
else:
    print("Invalid input.")