#include <iostream>
using namespace std;

int main(int argc, const char * argv[]) {
    int n;cin>>n;
    
    if(n==4)cout<<3<<endl;
    else if(n==6)cout<<5<<endl;
    else{
        if(4-n/7>=n%7)cout<<7<<endl;
        else cout<<8<<endl;
    }
    return 0;
}