p1.cpp

好东西,绝对是好东西,我向大家推荐

#include <iostream.h>
int main()
{
	long long n,s;
	while(cin>>n)
	{
		s=1;
		while(n!=1&&n!=0)
		{
			s=s*n;
			n--;
		}
		cout<<s<<endl;
	}
}