#include <stdio.h>

void main(void){
	int scoreList[6];
	
	for(int i = 0 ; i < 6;i++){
		scanf("%d",&scoreList[i]);
	}
	for(int i = 0;i< 6;i++){
		for(int j = i ;j < 6;j++){
			if(scoreList[i] > scoreList[j]){
				int num = scoreList[i];
				scoreList[i] = scoreList[j];
				scoreList[j] = num;
			}
		}
	}
	
	double ave = 0;
	for(int i = 1;i < 5;i++){
		ave += scoreList[i];
	}
	printf("%0.2f",ave/4);
	
}