#pragma GCC target("avx2")
#pragma GCC optimize("03")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std; typedef long double ld; typedef long long ll;
typedef unsigned long long ull;
#define endl "\n"
#define FOR(i,a,b) for(int i=(a);i<=(b);i++)
#define rep(i,n) for(int i=0;i<(n);i++)
#define PII pair<int, int>
#define PLL pair<ll, ll>
#define ALL(x) (x).begin(), (x).end()
constexpr int INF=1<<30; constexpr ll LINF=1LL<<60; constexpr ll mod=1e9+7; constexpr int NIL = -1;
template<class T>inline bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T>inline bool chmin(T &a, const T &b) { if (b<a) { a = b; return 1; } return 0; }
template<class T>inline int popcount(T a) {return __builtin_popcount(a);}
template<class T>inline T emod(T a, T p) { return (a%p + p) % p;}
//-------------------
int main() {
    cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(15);
    int n; cin >> n;
    vector<ld> perf(n);
    rep(i,n) {
        cin >> perf[i];
    }

    auto F = [](int n) {
        if(n==-1) {
            ld bunshi = sqrt(0.81/(1.0-0.81));
            ld bunbo = 0.90/ (1-0.90);
            return bunshi / bunbo;
        } else {
            ld bunshi = sqrt((0.81-0.81*pow(0.81, n))/(1.0-0.81));
            ld bunbo = (0.90-0.90*pow(0.90, n))/(1.0-0.90);
            return bunshi/bunbo;
        }
    };
    auto f = [&](int k) {
        return (F(k) - F(-1)) / (F(1) - F(-1)) * 1200;
    };

    auto g = [&](int i) {
        return pow(2.0, perf[i]/800);
    };

    ld pw9 = 1.0; 
    ld bunshi = 0.0;
    ld bunbo = 0.0;
    rep(i, n) {
        pw9 *= 0.9;
        bunshi += g(i) * pw9;
        bunbo += pw9;
    }

    ld x = bunshi/bunbo;
    ld ans = log(x)*800.0/log(2.0) - f(n);
    cout << (ll) ans << endl;
    return 0;
}