DSA03025 - TRỤC TỌA ĐỘ

//Made By Phuong Nam PROPTIT <3//
#pragma GCC Optimize("O3")
#include<bits/stdc++.h>
#define alphaa "abcdefghijklmnopqrstuvwxyz"
#define ALPHAA "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
#define f(i,a,b) for(int i=a;i<=b;i++)
#define f1(i,n) for(int i=1;i<=n;i++)
#define f0(i,n) for(int i=0;i<n;i++)
#define ff(i,b,a) for(int i=b;i>=a;i--)
#define el cout<<'\n'
#define fi first
#define se second
#define eb emplace_back
#define pk pop_back
#define vi vector<int>
#define vl vector<ll>
#define pii pair<int,int>
#define pll pair<ll,ll>
#define all(s) s.begin(),s.end()
using namespace std;
typedef long long ll;
const int N=1e6+3;
const int MOD=1e9+7;
template<class X,class Y>
    void minimize(X &x,const Y &y) {
        if (x>y) x=y;
    }
template<class X,class Y>
    void maximize(X &x,const Y &y) {
        if (x<y) x=y;
    }
template<class T>
    T Abs(const T &x) {
        return (x<0?-x:x);
    }
int n;
pii a[N];
bool ss(pii a,pii b)
{
    return a.se<b.se;
}
void xuly()
{
    cin>>n;
    f1(i,n) cin>>a[i].fi>>a[i].se;
    sort(a+1,a+n+1,ss);
    int res=a[1].se,dem=1;
    f(i,2,n)
    {
        if(res<=a[i].fi) dem++,res=a[i].se;
    }
    cout<<dem;el;
}
int main()
{
  ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
  int t=1;
  cin>>t;
  while(t--) xuly();
  return 0;
}
//-----YEU CODE HON CRUSH-----//