from itertools import *
from bisect import *
from math import *
from collections import *
from heapq import *
from random import *
from decimal import *
import numpy as np
import sys

sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def MI1(): return map(int1, sys.stdin.readline().split())
def MF(): return map(float, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LF(): return list(map(float, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
dij = [(0, 1), (1, 0), (0, -1), (-1, 0)]

def main():
    g = lambda x: 2 ** (x / 800)
    n = II()
    rps = [II() for _ in range(n)]
    Finf = 1 / 19 ** 0.5
    Fn = ((1 - 0.81 ** n) / 19) ** 0.5 / (1 - 0.9 ** n)
    fn = (Fn - Finf) / (1 - Finf) * 1200
    rating = 800 * log2(sum(g(rp) * 0.9 ** i for i, rp in enumerate(rps,1)) / 9 / (1 - 0.9 ** n)) - fn
    print(round(rating))

main()