#include<stdio.h>
#include<stdlib.h>

typedef long long int ll;

int MIN(int a, int b){return a>b?b:a;}
int MAX(int a, int b){return a>b?a:b;}
int compare(const void* a, const void* b){
    return *(int*)a - *(int*)b;
}

int main(void){
    int s[6];
    for(int i=0; i<6; i++){
        scanf("%d", &s[i]);
    }

    qsort(s, 6, sizeof(int), compare);

    double sum = 0.0;
    for(int i=0; i<6; i++){
        if(i==0 || i==5){
            continue;
        }
        sum += s[i];
    }

    printf("%l.2f\n", sum/4);
    return 0;
}