from math import sqrt, log2

def F(n):
    a, b = 0, 0
    for i in range(1, n + 1):
        a += pow(0.9, i)
        b += pow(0.81, i)
    return sqrt(b)/a

def f(n):
    return (F(n) - F(1000))/(F(1) - F(1000)) * 1200

def g(X):
    return pow(2, X/800)

N = int(input())
R = [0] * N
for i in range(N):
    R[i] = int(input())
a, b = 0, 0
for i in range(1, N + 1):
    a += g(R[i-1]) * pow(0.9, i)
    b += pow(0.9, i)
    
print(int(800*log2(a/b) - f(N)))