n,t;
double r,de,nu,co,Fn;
main(){
	scanf("%d",&n);
	r=0.9;
	while(n--){
		scanf("%d",&t);
		de+=r;
		nu+=r*pow(2,t/8e2);
		co+=r*r;
		r*=0.9;
	}
	Fn=sqrt(co)/de;
	printf("%.f",800*log2(nu/de)-1200*(Fn-1/sqrt(19))/(1-1/sqrt(19)));
}