ll@n,@a,@x[n],y[],d[]{},e[],@t,@(l,r)[t];
sortA_index(n,x,y);
rrep(i,t){
	ll a=bsearch_min[ll,j,0,n](x[j]>=l[i]);
	ll b=bsearch_min[ll,j,0,n](x[j]>r[i]);
	while(a<b){
		if(d[a]){
			(a,e[a])=(e[a],max(e[a],b));
		}else{
			d[a]=i+1;
			e[a]=b;
			++a;
		}
	}
}
rep(i,n){
	e[y[i]]=d[i]?:-1;
}
wtLn(e(n));