#include "bits/stdc++.h"
using namespace std;
#define FOR(i,a,b) for(int i =(a);i<(b);i++)
#define REP(i,n) for(int i=0;i<(n);i++)
#define REPm(i,n) for(int i=(n)-1;i>=0;i--)
#define REP1(i,n) for(int i=1;i<=(n);i++)
#define mp make_pair
typedef long long ll;
double g(int N,int i){
    return pow(2.0,((double)N)/800.0)*pow(0.9,i);
}
int main(){
    int n;
    cin >> n;
    double Fn = sqrt(1.0-pow(0.81,n))/(1.0-pow(0.9,n));
    double fn = 1200.0*(Fn-1)/(sqrt(19.0)-1);
    double sum = 0;
    REP1(i,n){
        int Perf;
        cin >> Perf;
        sum += g(Perf,i);
    }
    sum = sum/(9.0*(1.0-pow(0.9,n)));
    double ginv = 800*log(sum)/log(2.0);
    ginv -= fn;
    cout << (ll)round(ginv)<< endl;
    return 0;
}