#include <bits/stdc++.h> using namespace std; int main() { int a[6]; double sum = 0; for(int i = 1;i <= 4;i++) { cin>>a[i]; } int max = a[1],min = a[1]; for(int i = 1;i <= 4;i++) { if(a[i] > max) { max = a[i]; } else if(a[i] < min) { min = a[i]; } } for(int i = 1;i <= 4;i++) { if(a[i] == max || a[i] == min) { a[i] = 0; } sum += a[i]; } cout<<setprecision(2)<<fixed<<sum/2<<endl; return 0; }