#include<bits/stdc++.h>
#define AC return 0;
#define int long long 
#define pii pair<int,int>
#define all(tar) tar.begian(),tar.end()
const int maxx=2e5+5;
const int mod=998244353; 
using namespace std;
int n,m,t;

struct Line {
    int l, r;

    bool operator < (const Line &other) const {
        if (r != other.r)
            return r < other.r;
        return l < other.l;
    }
};

void Solve()
{
    int n;
    cin >> n;
    vector < Line > a(n + 1);
    for (int i = 1; i <= n; i++)
        cin >> a[i].l >> a[i].r;
    sort (a.begin() + 1, a.end());
    int x = -1;
    int res = 0;
    for (int i = 1; i <= n; i++)
    {
        if (x < a[i].l)
        {
            x = a[i].l + 1;
            res++;
        }
        else if(x >= a[i].l && x <= a[i].r)
        {
            x++;
            res++;
        }
    }
    cout << res << "\n";
}

signed main(){
   ios::sync_with_stdio(false);
   cin.tie(0);
   cout.tie(0);

    int T = 1;
    cin >> T;

    while (T--)
    {
        Solve();
    }

   AC
}