#include <bits/stdc++.h>

using i64 = long long;

void solve() {
    int n;
    std::cin >> n;
    
    std::vector<int> l(n), r(n);
    std::map<int, std::vector<int>> f;
    for (int i = 0; i < n; i++) {
        std::cin >> l[i] >> r[i];
        f[l[i]].push_back(i);
    }
    
    int ans = 0;
    std::priority_queue<int, std::vector<int>, std::greater<>> q;
    for (int i = 1; ; i++) {
        if (q.empty()) {
            auto it = f.lower_bound(i);
            if (it == f.end()) {
                break;
            }
            i = it->first;
        }
        for (auto j : f[i]) {
            q.push(r[j]);
        }
        while (!q.empty()) {
            int x = q.top();
            q.pop();
            
            if (x < i) {
                continue;
            }
            ans++;
            break;
        }
    }
    
    std::cout << ans << "\n";
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    int t;
    std::cin >> t;
    
    while (t--) {
        solve();
    }
    
    return 0;
}