#33952: ___.
#include <iostream>
using namespace std;
int main()
{
int c;
cin >> c;
cout <<(c%12)*5+(c-c%12)/12*50<<endl;
}
#include <iostream>
using namespace std;
int main()
{
int c;
cin >> c;
cout <<(c%12)*5+(c-c%12)/12*50<<endl;
}