import math

 """ The purpose is to find N! of the input number with For-Loop. N! = (N) * (N -1) * (N - 2) *...... * 3 * 2 * 1 """ */
n = 0
nFactorial = 1
n = input("Please enter a number : ")
if n > 0:
  if n > 1:
    for i in range(n, 1+1, -1):
      nFactorial = i * nFactorial
  else:
    pass
  print("" + n + "! = " + nFactorial)
else:
  if n == 0:
    print("" + n + "! = " + nFactorial)
  else:
    print("Can't find factorial on " + n)