#include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <cmath>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <bitset>
#include <cstring>
using namespace std;
#define FOR(I,A,B) for(int I = (A); I < (B); ++I)
#define CLR(mat) memset(mat, 0, sizeof(mat))
typedef long long ll;

int main()
{
  int N; cin >> N;
  double r[N];
  FOR(i,0,N) cin >> r[i];
  double Fn, fn, f1, finf;
  FOR(i,1,N+1) Fn += pow(0.81, i);
  Fn = sqrt(Fn);
  double tmp = 0;
  FOR(i,1,N+1) tmp += pow(0.9, i);
  Fn /= tmp;
  f1 = sqrt(0.81) / 0.9;
  finf = sqrt(0.81 / 0.19) / (0.9 / 0.1);
  fn = (Fn - finf) / (f1 - finf) * 1200;
  double ans = 0;
  FOR(i,1,N+1) {
    ans += pow(2, r[i-1] / 800.0) * pow(0.9, i);
  }
  ans /= tmp;
  ans = 800 * log(ans) / log(2);
  ans -= fn;
  cout << int(ans) << endl;
  return 0;
}