// {{{ Templates
#include <bits/stdc++.h>

#define show(x) cerr << #x << " = " << x << endl

using namespace std;
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;

template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v)
{
    os << "sz:" << v.size() << "\n[";
    for (const auto& p : v) {
        os << p << ",";
    }
    os << "]\n";
    return os;
}

template <typename S, typename T>
ostream& operator<<(ostream& os, const pair<S, T>& p)
{
    os << "(" << p.first << "," << p.second
       << ")";
    return os;
}


constexpr ll MOD = (ll)1e9 + 7LL;

template <typename T>
constexpr T INF = numeric_limits<T>::max() / 100;

// }}}

long double powsum(long double a, int n)
{
    const long double b = a / (1 - a);
    return b * (long double)(1 - pow(a, n));
}

long double F(int n)
{
    return sqrt((1 - pow(0.81, n)) / 19) / (1 - pow(0.9, n));
}

long double f(int n)
{
    const long double Finf = sqrt((long double)1.0 / 19);
    const long double bunsi = F(n) - Finf;
    const long double bunbo = F(1) - Finf;
    return bunsi * 1200 / bunbo;
}

long double g(long double x)
{
    return pow(2.0, x / 800);
}
long double ginv(long double x)
{
    return (long double)(800.0) * log2(x);
}

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    cin >> N;
    vector<long double> R(N);
    for (int i = 0; i < N; i++) {
        cin >> R[i];
    }

    long double bunsi = 0;
    const long double bunbo = powsum(0.9, N);
    long double num = 0.9;
    for (int i = 0; i < N; i++) {
        bunsi += g(R[i]) * num;
        num *= 0.9;
    }
    const long double rating = ginv(bunsi / bunbo) - f(N);
    cout << round(rating) << endl;

    return 0;
}