#include <bits/stdc++.h>
const int MaxN = 8e5 + 50;
template <class t>
inline void read(t &s) {
  s = 0;
  register int f = 1;
  register char c = getchar();
  while (!isdigit(c)) {
    if (c == '-') f = -1;
    c = getchar();
  }
  while (isdigit(c)) s = (s << 3) + (s << 1) + (c ^ 48), c = getchar();
  s *= f;
  return;
}
template <class t, class... A>
inline void read(t &x, A &...a) {
  read(x);
  read(a...);
}
template <class t>
inline void write(t x) {
  if (x < 0) putchar('-'), x = -x;
  int buf[21], top = 0;
  while (x) buf[++top] = x % 10, x /= 10;
  if (!top) buf[++top] = 0;
  while (top) putchar(buf[top--] ^ '0');
  return;
}
inline void setIn(std::string s) {
  freopen(s.c_str(), "r", stdin);
  return;
}
inline void setOut(std::string s) {
  freopen(s.c_str(), "w", stdout);
  return;
}
inline void setIO(std::string s = "") {
  setIn(s + ".in");
  setOut(s + ".out");
  return;
}
template <class t>
inline bool ckmin(t &x, t y) {
  if (x > y) {
    x = y;
    return 1;
  }
  return 0;
}
template <class t>
inline bool ckmax(t &x, t y) {
  if (x < y) {
    x = y;
    return 1;
  }
  return 0;
}
inline int lowbit(int x) { return x & (-x); }
int l[MaxN], r[MaxN], n;
int f[MaxN], g[MaxN];
inline void work() {
  read(n);
  std::vector<int> dr;
  for (int i = 1; i <= n; ++i)
    read(l[i], r[i]), dr.push_back(l[i]), dr.push_back(r[i]);
  std::sort((dr).begin(), (dr).end()),
      dr.erase(std::unique((dr).begin(), (dr).end()), dr.end());
  for (int i = 1; i <= n; ++i)
    l[i] = std::lower_bound((dr).begin(), (dr).end(), l[i]) - dr.begin() + 1,
    r[i] = std::lower_bound((dr).begin(), (dr).end(), r[i]) - dr.begin() + 1;
  for (int i = 1; i <= n; ++i) l[i] = l[i] * 2 - 1, r[i] = r[i] * 2 - 1;
  register int m = *std::max_element(r + 1, r + n + 1);
  std::memset(f, 0, sizeof(int) * (m + 5)),
      std::memset(g, 0, sizeof(int) * (m + 5));
  for (int i = 1; i <= n; ++i) ++f[l[i]], --f[r[i] + 1];
  for (int i = 1; i <= m + 1; ++i) f[i] += f[i - 1];
  register int all = 0;
  {
    register int flg = 0;
    for (int i = 1; i <= m; ++i)
      if (f[i])
        flg = 1;
      else
        all += flg, flg = 0;
    all += flg;
  }
  {
    register int flg = 0;
    for (int i = 1; i <= m; ++i)
      if (f[i] == 1)
        flg = 1;
      else
        g[i - 1] = flg, flg = 0;
    g[m] = flg;
  }
  for (int i = 1; i <= m + 1; ++i) g[i] += g[i - 1];
  register int ans = -514114;
  for (int i = 1; i <= n; ++i)
    ckmax(ans, g[r[i] - 1] - g[l[i] - 1] + (f[r[i]] == 1 && f[r[i] + 1] >= 1) -
                   (!f[l[i] - 1] && f[l[i]] == 1));
  write(ans + all), std::puts("");
}
signed main(void) {
  int t;
  read(t);
  while (t--) work();
  return 0;
}
