#include <iostream>
using namespace std;
int main()
{
/*
z:9.6*6;
z-max:9.4*5;
z-min:9.8*5;
max=9.6*6-9.4*5;
min=9.6*6-9.8*5;
z-max-min:???*4*/
printf("%5.2f", (9.6 * 6 - (9.6 * 6 - 9.4 * 5) - (9.6 * 6 - 9.8 * 5)) / 4);
// cout<<" 9.60";
return 0;
}