#include<string>
#include<deque>
#include<queue>
#include<vector>
#include<algorithm>
#include<iostream>
#include<set>
#include<cmath>
#include<tuple>
#include<chrono>
#include<functional>
#include<iterator>
#include<random>
#include<unordered_set>
#include<array>
#include<map>
using namespace std;
typedef long long int llint;
#define mp make_pair
#define mt make_tuple
#define pub push_back
#define puf push_front
#define pob pop_back
#define pof pop_front
#define fir first
#define sec second
#define res resize
#define ins insert
#define era erase
const int mod=1000000007;
const llint big=1e18+10;
const long double pai=3.141592653589793238462643383279502884197;
const long double eps=1e-9;
template <class T,class U>void mineq(T& a,U b){if(a>b){a=b;}}
template <class T,class U>void maxeq(T& a,U b){if(a<b){a=b;}}
int gcd(int a,int b){if(a%b==0){return b;}else return gcd(b,a%b);}

int main(void){
	int n,i,j;cin>>n;
	
	double f=0,F,Finf,g;
	double ue=0,st=0,ueg=1,stg=1;
	for(i=0;i<n;i++){
		ue+=ueg;
		st+=stg;
		ueg*=0.81;
		stg*=0.9;
	}
	F=sqrt(ue)/st;
	for(i=n;i<1000;i++){//1000=inf
		ue+=ueg;
		st+=stg;
		ueg*=0.81;
		stg*=0.9;
	}
	Finf=sqrt(ue)/st;
	f=((F-Finf)/(1-Finf))*1200;
	double kake=1,rui=0,raue=0;
	double perf;
	for(i=0;i<n;i++){cin>>perf;raue+=pow(2.0,perf/800.0)*kake;rui+=kake;kake*=0.9;}
	double late;
	late=(log(raue/rui)/log(2.0))*800-f;
	cout<<(int)late<<endl;
}