import math
N = int(input())
F = lambda n: math.sqrt(sum([0.81 ** i for i in range(1, n + 1)])) / sum([0.9 ** i for i in range(1, n + 1)])
g = lambda x: 2 ** (x / 800)
print(int(800 * math.log((sum([g(int(input())) * (0.9 ** i) for i in range(1, N + 1)]) / sum([0.9 ** i for i in range(1, N + 1)])), 2) - (F(N) - 1 / math.sqrt(19)) / (F(1) - 1 / math.sqrt(19)) * 1200))