#include<bits/stdc++.h>
using namespace std;

int main(){
    long long n;
    cin >> n;
    long long k = (n - n % 11) / 11, m = n % 11;
    long long l = (m - m % 5) / 5, v = m % 5;
    cout << k + l + v;
    return 0;
}