**Factorial of a number**

Factorial of any number n is represented by n! which is equal to 1*2*3*….*(n-1)*n.

E.g.:

4! = 1*2*3*4 = 24

3! = 3*2*1 = 6

2! = 2*1 = 2

Also,

1! = 1

0! = 1

Write a Python program to calculate factorial of any given number. If you enter a negative number, display “Factorial does not exist for negative numbers” and stop the program.

**Sample Input 1:**

Enter a number

5

**Sample Output 1:**

Factorial is 120

**Sample Input 2:**

Enter a number

0

**Sample Output 2:**

Factorial is 1

**Sample Input 3:**

Enter a number

-5

**Sample Output 3:**Factorial does not exist for negative numbers

**Code :-**

n=int(input("Enter a number\n")) f=1 if n<0: print("Factorial does not exist for negative numbers") exit() elif n==0: print("Factorial is 1") exit() else: for i in range(1,n+1): f=f*i print("Factorial is "+str(f))