#include <iostream>
#include <cmath>
using namespace std;
double g(double X){return pow(2.0,X/800);}
double g1(double X){return 800*log(X)/log(2);}
int main(){
	
	int n;
	double Fn,fn,F1=1,Finf=0.229416;
	
	cin>>n;
	double tmp1=0,tmp2=0;
	for(int i=1;i<=n;i++){
		tmp1+=pow(0.81,(double) i);
		tmp2+=pow(0.9,(double) i);
	}
	Fn=sqrt(tmp1)/tmp2;
	fn=(Fn-Finf)*1200/(F1-Finf);
	
	double X,RP,g_1;
	tmp1=tmp2=0;
	for(int i=1;i<=n;i++){
		cin>>RP;
		tmp1+=g(RP)*pow(0.9,(double) i);
		tmp2+=pow(0.9,(double) i);
	}
	cout<<(int) (g1(tmp1/tmp2)-fn)<<endl;
	
	return 0;
	
}