#include <bits/stdc++.h>
using namespace std;
const int N = 8e5 + 5;
int read() {
  int s = 0;
  char c = getchar(), lc = '+';
  while (c < '0' || '9' < c) lc = c, c = getchar();
  while ('0' <= c && c <= '9') s = s * 10 + c - '0', c = getchar();
  return lc == '-' ? -s : s;
}
void write(int x) {
  if (x < 0) putchar('-'), x = -x;
  if (x < 10)
    putchar(x + '0');
  else
    write(x / 10), putchar(x % 10 + '0');
}
void print(int x = -1, char c = '\n') {
  write(x);
  putchar(c);
}
int l[N], r[N], b[N];
int c[N], a[N], one[N];
signed main(signed Recall, char *_902_[]) {
  (void)Recall, (void)_902_;
  int T = read();
  while (T--) {
    int n = read(), cnt = 0, ans = -1, atfirst = 0, minl = 1919810111, maxr = 0;
    for (int i = 1; i <= n; i++)
      b[++cnt] = l[i] = read(), b[++cnt] = r[i] = read();
    sort(b + 1, b + 1 + cnt);
    cnt = unique(b + 1, b + 1 + cnt) - b - 1;
    for (int i = 1; i <= n; i++)
      l[i] = lower_bound(b + 1, b + 1 + cnt, l[i]) - b,
      r[i] = lower_bound(b + 1, b + 1 + cnt, r[i]) - b;
    for (int i = 1; i <= n; i++) l[i] = l[i] * 2 - 1, r[i] = r[i] * 2 - 1;
    for (int i = 1; i <= n; i++) minl = min(minl, l[i]), maxr = max(maxr, r[i]);
    cnt = cnt * 2 + 1;
    for (int i = 1; i <= n; i++) c[l[i]]++, c[r[i] + 1]--;
    for (int i = 1; i <= cnt; i++) c[i] += c[i - 1];
    for (int i = 1; i <= cnt; i++)
      if (c[i] == 1 && c[i - 1] > 1) a[i] = 1;
    for (int i = 1; i <= cnt; i++)
      if (c[i] == 1) one[i] = 1;
    for (int i = 1; i <= cnt; i++) one[i] += one[i - 1], a[i] += a[i - 1];
    for (int i = 1; i <= cnt; i++) atfirst += c[i] && !c[i - 1];
    for (int i = 1; i <= n; i++) {
      int l = ::l[i], r = ::r[i];
      if (one[r] - one[l - 1] == r - l + 1) {
        int now = !!c[l - 1] && !!c[r + 1];
        if (!c[l - 1] && !c[r + 1]) now = -1;
        ans = max(ans, now);
        continue;
      }
      int now = a[r] - a[l - 1];
      if (c[r] == 1 && (!c[r + 1] || r == maxr)) now--;
      if (c[l] == 1 && c[l - 1] && l > minl) now++;
      ans = max(ans, now);
    }
    print(ans + atfirst);
    for (int i = 1; i <= cnt; i++) c[i] = a[i] = one[i] = 0;
  }
  return 0;
}
