#include<bits/stdc++.h>

using namespace std;

struct singer {
	int score;
};

singer s[100][20];
singer aven[100];
int main() {
	int n , m;
	cin >> n >> m;
	
	int sum;
	int higher;
	int lower;
	
	higher = 0;
	lower = 10;


	for(int i = 0 ; i <= n - 1 ; i++) {
		for(int j = 0 ; j <= m - 1 ; j++) {
			cin >> s[i][j].score;
			if(s[i][j].score > higher)
			{
				higher = s[i][j].score;

			}
			if(s[i][j].score < lower)
			{
				lower = s[i][j].score;

			}
		}
	}

	for(int i = 0 ; i <= n - 1 ; i++) {
		for(int j = 0 ; j <= m - 1 ; j++) {

			sum += s[i][j].score;
		}
		sum -= higher;
		sum -= lower;
		aven[i].score = sum * 1.0 / (m - 2);
		sum = 0;
	}


	float maxn = aven[0].score;
	for(int i = 0 ; i <= n - 1 ; i++) {
		if(aven[i].score >= maxn) {
			maxn = aven[i].score;
		}
	}

	printf("%.2f",maxn);

	return 0;
}

麻烦大佬给我指点指点。