#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>

using namespace std;

double P(double x, int n) {
  return (1 - pow(x, n)) / (1 - x) * 0.9;
}

double F(int n) {
  return sqrt(P(0.81, n)) / P(0.9, n);
}

double f(int n) {
  return (F(n) - F(1000)) / (F(1) - F(1000)) * 1200;
}

int main() {
  int n;
  cin >> n;
  double ans = 0;
  for (int i = 1; i <= n; i++) {
    double r;
    cin >> r;
    ans += pow(2, r / 800) * pow(0.9, i);
  }
  ans /= P(0.9, n);
  ans = 800 * log2(ans) - f(n);

  cout << int(ans) << endl;
}