package tp1ex3;

import java.util.Scanner;

public class MainEx3 {
	
	public static int plusPetit(int []tab,int indiceMax) {
		int min = tab[0];
		for (int i=1; i<indiceMax; i++) {
			if (tab[i] < min) min = tab[i];
		}
		return min;
	}

	public static int plusGrand(int []tab,int indiceMax) {
		int max = tab[0];
		for (int i=1; i<indiceMax; i++) {
			if (tab[i] > max) max = tab[i];
		}
		return max;
	}
	

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int [] tableau = new int[1000];
		int indice = 0;
		
		do {
			int n = sc.nextInt();
			if (n==-1) break;
			tableau[indice] = n;
			indice++;
		} while(true);
		
		int min = plusPetit(tableau,indice);
		int max = plusGrand(tableau,indice);
		
		int somme = 0;
		for (int i=0; i<indice; i++) {
			somme += tableau[i];
		}
		somme -= min;
		somme -= max;
		
		double moyenne = ((double)somme)/((double)(indice-2));
		System.out.println(moyenne);
		
	}

}