int n,r,a[18],b[18];

struct M{
	int e[18][18];
};

M operator*(M const & a, M const & b){
	M c;
	rep(y,n)rep(x,n){
		c.e[y][x]=9999;
		rep(w,n)c.e[y][x]<?=max(a.e[y][w],b.e[w][x]);
	}
	return c;
}

M pow(M a,int n){
	M r;
	while(n){
		if(n&1) r=r*a,--n;
		else a=a*a, n>>=1;
	}
	return r;
}

{
	M m;
	rd(n,(a,b)(n));
	rep(y,n)rep(x,n)m.e[y][x]=y==x?9999:b[y]-a[y]+a[x];
	m=pow(m,n-1);
	r=9999;
	rep(y,n)rep(x,n)r<?=m.e[y][x];
	wt(r);
}