#include<bits/stdc++.h>

#define ll long long
#define mk make_pair
#define fi first
#define se second

using namespace std;

inline int read(){
	int x=0,f=1;char c=getchar();
	for(;(c<'0'||c>'9');c=getchar()){if(c=='-')f=-1;}
	for(;(c>='0'&&c<='9');c=getchar())x=x*10+(c&15);
	return x*f;
}

template<typename T>void cmax(T &x,T v){x=max(x,v);}
template<typename T>void cmin(T &x,T v){x=min(x,v);}

const int N=3e6+5;
int G[N],st[N],ed[N],n,Gv[N];

const int INF=1.1e9;
int dis[N],cnt[N];
bool inq[N];
bool spfa(int s){
//	cout<<"spfa "<<s<<endl;
	deque<int>q;int cont=0;
	for(int i=1;i<=n;i++)dis[i]=INF,cnt[i]=0,inq[i]=0;
	q.push_front(s),dis[s]=0,inq[s]=1;
	while(!q.empty()){
		int u=q.front();q.pop_front(),inq[u]=0;
//		cout<<"u = "<<u<<" dis = "<<dis[u]<<endl;
		for(int i=st[u];i<=ed[u];i++){
			int v=G[i],w=Gv[i];
//			cout<<" -> v,w = "<<v<<" "<<w<<endl;
			if(dis[v]>dis[u]+w){
				dis[v]=dis[u]+w,cnt[v]=cnt[u]+1;
				if(cnt[v]>=n)return false;
//				if(++cont>=30000000)return false;
				if(inq[v])continue;
				if(q.empty())q.push_back(v);
				else if(dis[v]>=dis[q.front()])q.push_back(v);
				else q.push_front(v);
				int f=q.front();q.pop_front();
				if(q.empty())q.push_back(f);
				int b=q.back();q.pop_back();
				if(dis[f]>dis[b])swap(f,b);
				q.push_front(f),q.push_back(b);
				inq[v]=1;
			}
		}
	}
//	cout<<"dis = ";for(int i=1;i<=n;i++)cout<<dis[i]<<" ";puts("");
	return true;
}

int V=0;
struct BIT{
	int c[N];
	void clear(int vv){for(int i=1;i<=vv;i++)c[i]=0;}
	int lowbit(int x){return x&(-x);}
	void add(int x){for(int i=x;i<=V;i+=lowbit(i))c[i]++;}
	int qsum(int x){int res=0;for(int i=x;i;i-=lowbit(i))res+=c[i];return res;}
}T;

vector<int>pos;
int calc(vector<pair<int,int> >Is){
	vector<int>lsh;pos.clear();
	for(auto [l,r]:Is)lsh.emplace_back(l),lsh.emplace_back(r);
	V=lsh.size();
	sort(lsh.begin(),lsh.end()),lsh.resize(unique(lsh.begin(),lsh.end())-lsh.begin());
//	cout<<"V = "<<V<<endl;
	for(auto &[l,r]:Is){
		l=lower_bound(lsh.begin(),lsh.end(),l)-lsh.begin()+1;
		r=lower_bound(lsh.begin(),lsh.end(),r)-lsh.begin()+1;
	}
	sort(Is.begin(),Is.end(),[&](pair<int,int>A,pair<int,int>B){return A.se<B.se;});
	for(auto [l,r]:Is)if(T.qsum(r)==T.qsum(l-1)){
		T.add(r);
		pos.emplace_back(lsh[r-1]);
//		cout<<"l,r = "<<lsh[l-1]<<" "<<lsh[r-1]<<endl;
//		cout<<"add point = "<<r<<endl;
	}
	
	int ans=0;
	for(auto [l,r]:Is)cmax(ans,T.qsum(r)-T.qsum(l-1));
	
	T.clear(V);
	return ans;
}

void solve(){
	n=read();
	vector<pair<int,int> >Is(n);
	vector<int>lsh;
	for(int i=0;i<n;i++)Is[i].fi=read(),Is[i].se=read();
	int t=calc(Is);
	if(t==1){
		cout<<t<<" "<<pos.size()<<" ";for(int x:pos)cout<<x<<" ";puts("");
		return ;
	}
//	cout<<"t = "<<t<<endl;
	for(auto &[l,r]:Is)r++;
	for(auto [l,r]:Is)lsh.emplace_back(l),lsh.emplace_back(r);
	sort(lsh.begin(),lsh.end()),lsh.resize(unique(lsh.begin(),lsh.end())-lsh.begin());
	
	for(auto &[l,r]:Is){
		l=lower_bound(lsh.begin(),lsh.end(),l)-lsh.begin()+1;
		r=lower_bound(lsh.begin(),lsh.end(),r)-lsh.begin()+1;
	}
	
	n=lsh.size();
	vector<int>deg(n+1);
	
	auto inse=[&](int u,int v,int w){deg[u]++,deg[v]++;};
	auto adde=[&](int u,int v,int w){st[u]--;G[st[u]]=v,Gv[st[u]]=w;return st[u];};
	
	// (x,y,z) : a[y] <= a[x] + z ---> a[y] - a[x] <= z
	
	for(int i=0;i+1<n;i++)inse(i+1,i+2,lsh[i+1]-lsh[i]),inse(i+2,i+1,0);
	for(auto [l,r]:Is)inse(r,l,-1),inse(l,r,t-1);
	
	for(int i=1;i<=n;i++)deg[i]+=deg[i-1],st[i]=deg[i]+1,ed[i]=deg[i];
	
	for(int i=0;i+1<n;i++)adde(i+1,i+2,lsh[i+1]-lsh[i]),adde(i+2,i+1,0);
	for(auto [l,r]:Is)adde(r,l,-1),adde(l,r,t-1);
	
	if(!spfa(1)){
		cout<<t<<" "<<pos.size()<<" ";for(int x:pos)cout<<x<<" ";puts("");
		return ;
	}
	vector<int>vals;
	for(int i=1;i<=n;i++){
		int cnt=dis[i+1]-dis[i];
		if(cnt>t-1)continue;
		for(int j=lsh[i-1];j<=lsh[i-1]+cnt-1;j++)vals.emplace_back(j);
	}
	
	cout<<t-1<<" "<<vals.size()<<" ";for(int x:vals)cout<<x<<" ";puts("");
}

signed main(void){

#ifndef ONLINE_JUDGE
	freopen("in.in","r",stdin);
//	freopen("out.out","w",stdout);
#endif

	int tt=read();while(tt--)solve();

	return 0;
}