#include<iostream>	
 using namespace std;
int main()	
{
	
 
	int num,factorial=1;
	  
	cin>>num;
 
	for(int i=1;i<=num;i++)
	{
		factorial=factorial*i;
	}
 
	cout<<factorial<<endl;
 
	cin.get();
 
	return 0;
}