#include<iostream>
#include<algorithm>
#include<cmath>
using namespace std;
#define int long long

signed main(){
	int a;
	cin>>a;
	if(a<5){
		cout<<a;
	}
	else if(a%5==0){
		cout<<a/5;
	}
	else if(a%11==0){
		cout<<a/11;
	}
	else{
		if(a%11>a%5){
			cout<<floor(a/5)+a%5;
		}
		else if(a%5>a%11){
			cout<<floor(a/11)+a%11;
		}
		else{
			cout<<floor(a/11)+a%11;
		}
	}
}