Factorial in Python

num=int(input("Enter an integer to find factorial : "))
fact=1
if num<0:
        print("Factorial of negative numbers does not exist.")
elif num==0:
        print("Factorial of 0 is 1.")
elif num==1:
        print("Factorial of 1 is 1.")
else:
        for i in range(1,num+1):
                fact=fact*i
        print("Factorial of ",num," is ",fact)

Output