#include <iostream.h>


long double frac(unsigned int a)
{/*	returns fractional of a
  *			frac(a) = a! = 1 * 2 * 3 * 4 * ... * a
  */
	long double result = 1;
	for(unsigned int i = 1; i<=a;i++)
	{
		result = result*i;
	}
	return result;
}

void main()
{
	unsigned int a = 0;

	cout << "geef getal : ";
	cin >> a;

	cout << "a! = " << frac(a) << endl;

}