#include <stdio.h>

int main(void){
	int n[1000];
	int i,num,flag,tmp;
	float result;

	scanf("%d",&num);

	for(i=0; i<num; i++){
		scanf("%d",&n[i]);
	}

	flag = 1;
	while(flag == 1){
		flag = 0;
		for(i=0; i<num-1; i++){
			if(n[i] > n[i+1]){
				tmp = n[i+1];
				n[i+1] = n[i];
				n[i] = tmp;
				flag = 1;
			}
		}
	}

	if(num%2 == 0){
		result = (n[num/2-1]+n[num/2])*1.0/2;
	}else{
		result = n[num/2]*1.0;
	}

	printf("%.1f\n",result);

	return 0;
}