double F(n){
	double a=0,b=0;int i=0;
	for(;i++<n;)a+=powl(0.81,i),b+=powl(0.9,i);
	return sqrtl(a)/b;
}
double Fi;
double f(n)
{
	return (F(n)-Fi)/(F(1)-Fi)*12e2;
}
double g(double x){
	return powl(2,x/800);
}
double iG(double x)
{
	return 800*log2l(x);
}
main(n)
{
	double x[150],r,G,H;
	int i=0,j;
	for(scanf("%d",&n);~scanf("%lf",x+i);i++);
	j=G=H=0;
	Fi=F(1e6);
	for(;j++<n;)G+=g(x[j-1])*powl(0.9,j),H+=powl(0.9,j);
	r=iG(G/H)-f(n);
	printf("%.lf\n",r);
}