#include<bits/stdc++.h>
using namespace std;
int main(){
	//freopen(".in","r",stdin);
	//freopen(".out","w",stdout);
	int n;
	cin>>n;
	int dp[100005];
	dp[1]=0;
	for(int i=2;i<=n;i++){
		dp[i]=min(dp[i-1],min(dp[i-5],dp[i-5]));
	}
	int ans=INT_MAX;
	for(int i=1;i<=n;i++){
		ans=min(dp[i],ans);
	}
	cout<<ans;
	
	return 0;
}