/* -*- coding: utf-8 -*-
 *
 * 553.cc: No.553 AlphaCoder Rating - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 100;
const int INF = 1 << 30;

/* typedef */

/* global variables */

int rps[MAX_N];

/* subroutines */

inline double sumexp(double p, int n) { // sum_(i=1..n) p^i
  return p * (1.0 - pow(p, (double)n)) / (1.0 - p);
}

inline double sumexpinf(double p) { // sum_(i=1..inf) p^i
  return p / (1.0 - p);
}

inline double F(int n) {
  return
    (n >= INF) ?
    sqrt(sumexpinf(0.81)) / sumexpinf(0.9) :
    sqrt(sumexp(0.81, n)) / sumexp(0.9, n);
}

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

inline double g(double x) { return pow(2.0, x / 800); }

// y = 2.0^(x/800) -> x/800 = log2(y) -> x = log2(y) * 800;
inline double invg(double x) {
  return log(x) / log(2.0) * 800;
}

double rat(int n) {
  double sum = 0.0, d = 0.9;
  for (int i = 0; i < n; i++, d *= 0.9)
    sum += g((double)rps[i]) * d;
  return invg(sum / sumexp(0.9, n))  - f(n);
}

/* main */

int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d", &rps[i]);

  double r = rat(n);
  printf("%d\n", (int)r);
  return 0;
}