include Math
n = gets.to_i
tmp = 1
tmp2 = 1
hoge = 0
foo = 0
bar = 0
1.upto(n) do |i|
    r = gets.to_f
    tmp *= 0.9
    tmp2 *= 0.81
    hoge += (2 ** (r / 800)) * tmp
    foo += tmp
    bar += tmp2
end
ans = 800 * log2(hoge / foo)
tmp = 1 / (19 ** 0.5)
ans -= ((bar ** 0.5 / foo - tmp) / (1 - tmp)) * 1200
p ans.round.to_i