#define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream> 
#include <random>
#include<map>
#include <iomanip>
#include <time.h>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
#include <cassert>
#include<fstream>
#include <unordered_map>  
using namespace std;
#define eps 0.00000001
#define LONG_INF 10000000000000000
#define GOLD 1.61803398874989484820458
#define MAX_MOD 1000000007
#define REP(i,n) for(long long i = 0;i < n;++i)
map<long long, double> aa,bb;
double F(long long n) {
	if (aa[n]) return aa[n];
	double bunbo = 0,bunsi = 0;
	double a = 1, b = 1;
	for (int i = 0;i < n;++i) {
		a *= 0.9;
		b *= 0.81;
		bunsi += b;
		bunbo += a;
	}
	bunsi = sqrt(bunsi);
	return aa[n] = bunsi / bunbo;
}
double f(long long n) {
	if (bb[n]) return bb[n];
	double bunsi = F(n);
	double bunbo = F(1);
	bunbo -= F(10000000);
	bunsi -= F(10000000);
	bunsi *= 1200;
	return bb[n] = bunsi / bunbo;
}
double g(double x) {
	return pow(2.0, x / 800.0);
}
double g_gyaku(double x) {
	return 800.0*log2(x);
}
int main() {
	int n;
	cin >> n;
	double bunbo = 0;
	double bunsi = 0;
	double left = 1;
	for (int i = 0;i < n;++i) {
		double hoge;
		cin >> hoge;
		left *= 0.9;
		bunbo += left;
		bunsi += left * g(hoge);
	}
	cout << round(g_gyaku(bunsi / bunbo) - f(n)) << endl;
	return 0;
}