#include <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <functional>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
#include <stack>

#ifdef LOCAL
template <class T, size_t size = std::tuple_size<T>::value> std::string to_debug(T, std::string s = "") requires(not std::ranges::range<T>);
std::string to_debug(auto x) requires requires(std::ostream& os) { os << x; } { return static_cast<std::ostringstream>(std::ostringstream() << x).str(); }
std::string to_debug(std::ranges::range auto x, std::string s = "") requires(not std::is_same_v<decltype(x), std::string>) {
  for (auto xi : x) { s += ", " + to_debug(xi); }
  return "[" + s.substr(s.empty() ? 0 : 2) + "]";
}
template <class T, size_t size> std::string to_debug(T x, std::string s) requires(not std::ranges::range<T>) {
  [&]<size_t... I>(std::index_sequence<I...>) { ((s += ", " + to_debug(get<I>(x))), ...); }(std::make_index_sequence<size>());
  return "(" + s.substr(s.empty() ? 0 : 2) + ")";
}
#define debug(...) std::cerr << __LINE__ << ": (" #__VA_ARGS__ ") = " << to_debug(std::tuple(__VA_ARGS__)) << "\n"
#else
#define debug(x...)
#endif

using i64 = long long;
#define int long long
using namespace std;
void solve()
{
#define tests
    int n; std::cin >> n;
    std::vector<std::pair<int, int>> a(n); for (auto&[l, r] : a) {std::cin >> l >> r;}
    std::sort(std::begin(a), std::end(a), [&](auto& i, auto& j) {
        if (i.second == j.second) {
            return i.first > j.first;
        } 
        return i.second > j.second;
    });

    int lst{std::numeric_limits<int>::max()};
    vector<bool>vis(n);
    int ans{}; 
    unordered_map<int,bool>p;
    while(1){
        bool ok=false;
        lst=1e9+7;
        for (int i = 0; i < n; i++) {
            auto&[l, r]{a.at(i)};
            if(vis[i])continue;
            //while(p[lst])lst--;

            for(int j=min(r,lst);j>=l;j--){
                if(!p[j]){
                    p[j]=1;
                    vis[i]=1;
                    ans++;
                    ok=true;
                    lst=j-1;
                    break;
                }
            }
            //cout<<i<<" "<<lst<<endl;
            // if (lst>=l) {
            //     ans += 1;
            //     vis[i]=1;
            //     ok=true;
            //     p[min(lst,r)]=1;
            //     lst = std::min(lst - 1, r - 1);
            //     //p[lst]=true;
            // }
        }
        if(!ok)break;
    }
    

    std::cout << ans << "\n";


}
 
signed main()
{
    std::cin.tie(nullptr)->sync_with_stdio(false);
    int _{1};
#ifdef tests
    std::cin >> _;
#endif
    while(_--) solve();
    return 0;
}