#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>

void main(void){
	int n = 0;
	int inputN = scanf("%d\n",&n);
	if(inputN == 2){
		printf("nの入力ミス\n");
	}
	double median = 0;
	int *numberList = (int *)malloc((size_t)n * sizeof(int));
	for(int i = 0;i < n;i++){
		int inputSum = scanf("%d",&numberList[i]);
		if(inputSum == 2){
			printf("Sumの入力ミス\n");
		}
	}
	for(int i = 0 ; i < n ; i ++){
		for(int j = 0 ; j < n ; j ++){
			if(numberList[i] > numberList[j]){
				int num = numberList[i];
				numberList[i] = numberList[j];
				numberList[j] = num;
			}
		}
	}
	if(n%2 != 0){
		median = numberList[n/2];
		printf("%0.01f\n",(double)numberList[n/2]);
		//printf("取得値:%d\n",numberList[n/2]);
	} else {
		printf("%0.01f\n",(double)(numberList[n/2] + numberList[n/2-1]) /2);
		//median = (numberList[n/2] + numberList[n/2-1]) /2;
		//printf("取得値:%dと%d\n",numberList[n/2],numberList[n/2-1]);
		//printf("取得値合計:%d\n",numberList[n/2]+numberList[n/2-1]);
	}
	free(numberList);
	//printf("%0.1f\n",median);
}