n,*a = map(int,open(0).read().split())

def h(r,n):
    return (r - r**(n+1))/(1-r)

def F(n):
    return (h(0.81,n)**0.5)/(h(0.9,n))

def f(n):
    return (F(n) - F(100000))/(F(1) - F(100000))*1200

from math import log
v = 0
for i in range(n):
    v += (2.0**(a[i]/800))*(0.9**(i+1))
v /= h(0.9,n)
ans = 800*log(v,2) - f(n)

print(int(ans))