#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize(2)
int t;
int tree[802000];
void add(int x, int num) {
  while (x <= 801000) {
    tree[x] += num;
    x += x & -x;
  }
}
int query(int x) {
  int ans = 0;
  while (x) {
    ans += tree[x];
    x -= x & -x;
  }
  return ans;
}
int c[802000], b[802000];
void solve() {
  vector<int> l, r, a;
  int x, y, n, mx = 0;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> x >> y;
    l.push_back(x);
    r.push_back(y);
    a.push_back(x);
    a.push_back(y);
  }
  sort(a.begin(), a.end());
  int p = unique(a.begin(), a.end()) - a.begin();
  for (auto& u : l) {
    u = lower_bound(a.begin(), a.begin() + p, u) - a.begin() + 1;
    u <<= 1;
  }
  for (auto& u : r) {
    u = lower_bound(a.begin(), a.begin() + p, u) - a.begin() + 1;
    u <<= 1;
  }
  for (int i = 0; i < n; i++) {
    add(l[i], 1);
    add(r[i] + 1, -1);
    mx = max(mx, r[i]);
  }
  mx++;
  for (int i = 1; i <= mx; i++) {
    b[i] = query(i);
  }
  int ans = 0, mmax = INT_MIN, flag0 = 0, cnt = 1;
  for (int i = 1; i <= mx; i++) {
    if (!b[i] && b[i - 1]) ans++;
  }
  for (int i = 1; i <= mx; i++) {
    if (b[i] > 1) c[i] = cnt;
    if (b[i] <= 1) {
      int p = i;
      flag0 = 0;
      while (b[p] <= 1 && p <= mx) {
        if (!b[p]) flag0 = 1;
        p++;
      }
      if (!flag0) cnt++;
      for (int j = i; j <= p; j++) c[j] = cnt;
      i = p;
    }
  }
  for (int i = 0; i < n; i++) {
    int tt = c[r[i]] - c[l[i]];
    if (c[r[i]] == c[l[i]] && b[l[i]] == 1 && b[r[i]] == 1) tt = -1;
    mmax = max(mmax, tt);
  }
  cout << ans + mmax << '\n';
  for (int i = 0; i < n; i++) {
    add(l[i], -1);
    add(r[i] + 1, 1);
  }
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  cin >> t;
  while (t--) solve();
  return 0;
}
