#include<stdio.h>
main(){
    int N;
    int max = 0;
    int min = 100;
    int sum = 0;
    for(int i = 0;i < 6;i++){
        scanf("%d",&N);
        sum += N;
        if(N > max){max = N;}
        if(N < min){min = N;}
    }
    printf("%.2lf\n",1.*(sum-max-min)/4);
}