#include <stdio.h>

int main(){
    int i, point[6];
    int max = 0, min = 100, sum = 0;
    double ave;

    for(i = 0; i < 6; i++){
        scanf("%d", &point[i]);
        if(max <= point[i]) max = point[i];
        if(min >= point[i]) min = point[i];
        sum += point[i];
    }

    ave = (sum - max - min)/4.0;

    printf("%.2lf\n", ave);

    return 0;
}