ll@n,@a[n],@b[n];
double c[n];
rep(i,n){
	c[i]=a[i]?double(b[i])/a[i]:0;
}
sortA(n,c,a,b);
ll s=sum(a(n));
rep(i,n){
	s-=a[i]*2;
	if(s<0){
		wt(Mint(b[i])/a[i]);
		exit(0);
	}
}