#!/usr/bin/evn python

# Take input from the user
num = int(input("Enter a number to calculate factorial: "))
factorial = 1

# Check if the number is negative, positive or zero
if num < 0:
    print("Sorry, factorial does not exist for negative numbers")
elif num == 0:
    print("The factorial of 0 is 1")
else:
    # For loop iterating by sequence index
    for i in range(1,num + 1):
        factorial = factorial*i
    print("The factorial of",num,"is",factorial)
    
    
    
#***** Output *****
Enter a number to calculate factorial: 5
The factorial of 5 is 120