a=1
try:
    n=int(input())
    if(0<=n<=20):
        for i in range(1,n+1):
            a=a*i
        print(a)
    else:
        print("Invalid input")
except ValueError:
    print("Invalid input")

3653b36bba0ac3a1a4c3b1366c79af836cf21d04
<mask token>

<mask token>
try:
    n = int(input())
    if 0 <= n <= 20:
        for i in range(1, n + 1):
            a = a * i
        print(a)
    else:
        print('Invalid input')
except ValueError:
    print('Invalid input')

a = 1
try:
    n = int(input())
    if 0 <= n <= 20:
        for i in range(1, n + 1):
            a = a * i
        print(a)
    else:
        print('Invalid input')
except ValueError:
    print('Invalid input')

a=1
try:
    n=int(input())
    if(0<=n<=20):
        for i in range(1,n+1):
            a=a*i
        print(a)
    else:
        print("Invalid input")
except ValueError:
    print("Invalid input")
