#include<iostream>

#include<cstdio>

#include<cstring>

using namespace std;

#define ll long long

#define ls rt<<1,l,m

#define rs rt<<1|1,m+1,r

#define pb push_back

const int INF=0x3f3f3f3f;

const int N=1e4+;

int st[N],ed[N];

bool vis[N]={false};

int ans;

void dfs(int l,int r,int x)

{

    if(x==)return ;

    if(l<=ed[x]&&r>=st[x])

    {

        if(!vis[x])

        {

            ans++;

            vis[x]=true;

        }

        if(l<st[x])dfs(l,st[x]-,x-);

        if(r>ed[x])dfs(ed[x]+,r,x-);

    }

    else dfs(l,r,x-);

}

int main()

{

    int c,n;

    scanf("%d",&c);

    while(c--)

    {

        scanf("%d",&n);

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

        {

            scanf("%d%d",&st[i],&ed[i]);

        }

        ans=;

        memset(vis,false,sizeof(vis));

        dfs(,,n);

        printf("%d\n",ans);

    }

    return ;

}