p1.cpp

好东西,绝对是好东西,我向大家推荐

#include<iostream.h>
int main()
{
	int s,N;
	while(cin>>N)
	{
		s=0;
		while(N>=5)
		{
			s+=N/5;
			N=N/5;
		}
		cout<<s<<endl;
	}
}