ll@t;
rep(t){
	ll@n,@m,@l[n],@r[n];
	if(sum(l(n))>m||sum(r(n))<m){
		wt(-1);
	}else{
		ll a=-1,b=m+2;
		while(a+1<b){
			ll c=a+b>>1;
			ll s=0;
			rep(i,n){
				s+=min(max(c,l[i]),r[i]);
			}
			if(s<=m){
				a=c;
			}else{
				b=c;
			}
		}
		ll s=m;
		rep(i,n){
			s-=min(max(a,l[i]),r[i]);
		}
		ll y=0,z=0;
		rep(i,n){
			ll x=min(max(a,l[i]),r[i]);
			if(s>0&&x==a&&x<r[i]){
				--s;
				++x;
			}
			z+=y*x;
			y+=x;
		}
		wt(z);
	}
}