#include <iostream>

using namespace std ;

constexpr int factorial(int n)
{
  if (n <= 1)
  {
    return 1;
  }
  else
  {
    return n * factorial(n - 1) ;
  }
}


int main()
{
	 constexpr int val = factorial(5)  ;
    cout << val << endl ;

 return 1 ;
}