#include <bits/stdc++.h>
#define N 400011
using namespace std;
int t,n,l[N],r[N],m,ned[N],mnl[N];
bool dp[N];int w[N],tow[N][21];
vector<int> vv;
int nxt[N];
int getw(int u,int k)
{
	for(int i=17;~i;--i)if(~u&&(k>>i&1))u=tow[u][i];
	return u;
}
bool check(int X)
{
	// printf("============================check(X:%d)\n",X);
	for(int i=1;i<=m+1;++i)nxt[i]=w[i]=-1,dp[i]=0;
	for(int i=1;i<=m+1;++i)for(int j=0;j<=17;++j)tow[i][j]=-1;
	int lst=0;
	for(int i=1;i<=m+1;++i)
	{//printf(">>>>>>>>i:%d\n",i);
		if(!~ned[i])
		{
			// printf("<>no pre success\n");
			w[i]=tow[i][0]=-1;
			for(int j=1;j<=17;++j)tow[i][j]=-1;
			dp[i]=1;
			while(lst<i)nxt[++lst]=i;
			continue;
		}
		if(!~nxt[ned[i]])return 0;
		int u=nxt[ned[i]],v=getw(u,X-1);
		if(mnl[i]>v)
		{
			// printf("<>success w:%d\n",u);
			dp[i]=1;
			w[i]=u;
			tow[i][0]=w[i];
			for(int j=1;j<=17;++j)tow[i][j]=tow[tow[i][j-1]][j-1];
			while(lst<i)nxt[++lst]=i;
		}
	}
	// printf("dp:");for(int i=1;i<=m+1;++i)printf("%d ",dp[i]);putchar(10);
	// printf("w:");for(int i=1;i<=m+1;++i)printf("%d ",w[i]);putchar(10);
	return dp[m+1];
}
int main()
{
	scanf("%d",&t);while(t--)
	{
		scanf("%d",&n);vv.clear();
		for(int i=1;i<=n;++i)scanf("%d%d",l+i,r+i),vv.push_back(l[i]),vv.push_back(r[i]),vv.push_back(l[i]-1),vv.push_back(r[i]+1);
		// if(t==691)
		// {
		// 	printf("%d\n",n);
		// 	for(int i=1;i<=n;++i)printf("%d %d\n",l[i],r[i]);
		// }
		sort(vv.begin(),vv.end());vv.resize(unique(vv.begin(),vv.end())-vv.begin());
		m=vv.size();
		for(int i=1;i<=n;++i)
		{
			l[i]=lower_bound(vv.begin(),vv.end(),l[i])-vv.begin()+1;
			r[i]=lower_bound(vv.begin(),vv.end(),r[i])-vv.begin()+1;
		}
		// printf("new intervals:");for(int i=1;i<=n;++i)printf("[%d,%d] ",l[i],r[i]);putchar(10);
		for(int i=0;i<=m+1;++i)ned[i]=-1;
		for(int i=1;i<=n;++i)ned[r[i]+1]=max(ned[r[i]+1],l[i]);
		for(int i=1;i<=m+1;++i)ned[i]=max(ned[i],ned[i-1]);
		for(int i=1;i<=m+1;++i)mnl[i]=1e9;
		for(int i=1;i<=n;++i)mnl[r[i]]=min(mnl[r[i]],l[i]);
		for(int i=m;i;--i)mnl[i]=min(mnl[i+1],mnl[i]);
		// printf("ned:");for(int i=1;i<=m+1;++i)printf("%d ",ned[i]);putchar(10);
		// printf("mnl:");for(int i=1;i<=m+1;++i)printf("%d ",mnl[i]);putchar(10);
		int L=1,R=n,ans=0;
		while(L<=R)
		{
			int M=L+R>>1;
			if(check(M))ans=M,R=M-1;else L=M+1;
		}
		check(ans);
		int tt=w[m+1];
		static vector<int> res;res.clear();
		while(~tt)
		{
			res.push_back(vv[tt-1]);
			tt=w[tt];
		}
		reverse(res.begin(),res.end());
		printf("%d %d ",ans,(int)res.size());
		for(int x:res)printf("%d ",x);
		putchar(10);
	}
	fclose(stdin);fclose(stdout);return 0;
}