import sys
def main():
    param = []
    for i in range(2):
        param.append(sys.stdin.readline())
    data_list = param[1].split(" ")
    data_list.sort()
    data_list = tuple(data_list)
    if len(data_list) % 2 == 1:
        #print("odd")
        omid_index = len(data_list) // 2
        print(data_list[omid_index])
    else:
        #print("even")
        emid_index1 = len(data_list) // 2 - 1
        emid_index2 = len(data_list) // 2
        emid1 = int(data_list[emid_index1])*1.0
        emid2 = int(data_list[emid_index2])*1.0
        mid_ave = (emid1+emid2)/2.0
        print(mid_ave)
        
if __name__ == "__main__":
    main()