if __name__ == "__main__":
	len = int(input())
	ls = sorted(list(map(int, input().split())))
	
	if len % 2 == 0:#偶数個の場合
		median = (ls[len//2-1] + ls[len//2])/2
	else:
		median = ls[len//2]
		
	print(median)