#include<stdio.h>

#include<string.h>

#include<iostream>

#include<algorithm>

using namespace std;

int n;

int g[][];

int vis[];

int link[];

int m;

int minn, maxx;

int dfs(int x)

{

    for (int y=minn; y<=maxx; ++y)

    {

        if (!vis[y] && g[x][y])

        {

            vis[y] = ;

            if (link[y] ==  || dfs(link[y]))

            {

                link[y] = x;

                return ;

            }

        }

    }

    return ;

}

void search()

{

    for (int x=n; x>=; --x)

    {

        memset(vis, , sizeof(vis));

        if (dfs(x)) m++;

    }

}

int main()

{

    int t;

    cin >> t;

    while(t--)

    {

        cin >> n;

        m = ;

        memset(g, , sizeof(g));

        memset(vis, , sizeof(vis));

        memset(link, , sizeof(link));

        minn = , maxx = -;

        for (int i=; i<=n; ++i)

        {

            int x, y;

            cin >> x >> y;

            if (minn > x) minn = x;

            if (maxx < y) maxx = y;

            for (int j=x; j<=y; ++j)

            {

                g[i][j] = ;

            }

        }

         search();

         cout << m << endl;

         int ans[];

         memset(ans, , sizeof(ans));

         int cnt = ;

         for (int x=minn; x<=maxx; ++x)

         {

             if (link[x] != )

             {

                ans[cnt++] = link[x];

             }

         }

         sort(ans, ans+cnt);

         for (int i=; i<cnt; ++i)

         {

             if (i != ) cout << ' ';

             cout << ans[i];

         }

         cout << endl;

    }

    return ;

}