total_num = int(input())
materials = input().split()

for key,value in enumerate(materials):
  materials[key] = int(value)

materials.sort()
total_value = (materials[0] + materials[1]) / 2

# 最初の2つを除去する
materials.pop(0)
materials.pop(0)

for index,value in enumerate(materials):
  if(index + 1 <= total_num - 2):
    total_value = (total_value + materials[index]) / 2
  else:
    break;

print(int(total_value))