#include <bits/stdc++.h>
using namespace std;
#define repl(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define rep(i,n) repl(i,0,n)
#define mp(a,b) make_pair((a),(b))
#define pb(a) push_back((a))
#define all(x) (x).begin(),(x).end()
#define uniq(x) sort(all(x)),(x).erase(unique(all(x)),end(x))
#define fi first
#define se second
#define dbg(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
void _dbg(string){cout<<endl;}
template<class H,class... T> void _dbg(string s,H h,T... t){int l=s.find(',');cout<<s.substr(0,l)<<" = "<<h<<", ";_dbg(s.substr(l+1),t...);}
template<class T,class U> ostream& operator<<(ostream& o, const pair<T,U> &p){o<<"("<<p.fi<<","<<p.se<<")";return o;}
template<class T> ostream& operator<<(ostream& o, const vector<T> &v){o<<"[";for(T t:v){o<<t<<",";}o<<"]";return o;}

#define INF 1120000000

int n;
double v[200];
double s9;

double Fn(){
  double p = 0;
  rep(i,n) p += pow(0.81, i+1.0);
  return sqrt(p) / s9;
}
double Finf(){
  return sqrt(81.0/19.0)/9.0;
}

double fn(){
  return 1200.0*(Fn()-Finf())/(1.0-Finf());
}

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

int main(){
  cin>>n;
  rep(i,n) cin>>v[i];

  s9 = 0;
  rep(i,n) s9 += pow(0.9, i+1.0);

  double q = 0;
  rep(i,n) q += g(v[i])*pow(0.9,i+1.0);

  double r = gi(q / s9) - fn();

  r += 0.5;
  int ans = r;
  cout << ans << endl;

  return 0;
}