#include <algorithm>
#include <cstdlib>
#include <iostream>
#include <vector>
#include <math.h>
using namespace std;
#define int long long
double f(int n) {
	double s1 = 0;
	double s2 = 0;
	for (int i = 1; i <= n; i++) {
		s1 += pow(0.81, i);
		s2 += pow(0.9, i);
	}
	return sqrt(s1) / s2;
}
signed main() {
	int N;
	cin >> N;
	vector<double> A(N);
	for (int i = 0; i < N; i++) {
		cin >> A[i];
	}
	double f1, fn, fi;

	f1 = f(1);
	fn = f(N);
	fi = f(10000);
	double ff = ((fn - fi) / (f1 - fi)) * 1200;
	double res;
	double s1 = 0;
	double s2 = 0;
	for (int i = 1; i <= N; i++) {
		s1 += pow(2, A[i - 1] / 800)*pow(0.9, i);
		s2 += pow(0.9, i);
	}
	res = 800 * log2(s1 / s2) - ff;
	cout << (int)(res + 0.5) << endl;
	return 0;
}