#include <iostream>
using namespace std;

int main()
{
    int g;
    cin>>g;
    g = g/8*2;

    if(g == 2.4375)
    {
        cout<<g*32/3+18<<endl;
    }
    else if(g == 8)
    {
        cout<<2*g*10/4<<endl;
    }
    else if(g == 9.75)
    {
        cout<<g*12/13+38<<endl;
    }
    else
    {
        cout<<g+47<<endl;
    }

    return 0;
}