#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 * 4;
inline int g() {
  int x;
  cin >> x;
  return x;
}
inline long long gl() {
  long long x;
  cin >> x;
  return x;
}
inline char gc() {
  char x;
  cin >> x;
  return x;
}
inline string gs() {
  string s;
  cin >> s;
  return s;
}
template <typename T>
inline vector<T> gv(int len) {
  vector<T> a(len);
  for (auto &it : a) cin >> it;
  return a;
}
inline vector<int> gv(int len) {
  vector<int> a(len);
  for (auto &it : a) cin >> it;
  return a;
}
inline vector<pair<int, int>> gv_andPairCnt(int len) {
  vector<pair<int, int>> a(len);
  int i = 1;
  for (auto &it : a) {
    it.second = i;
    i++;
    cin >> it.first;
  }
  return a;
}
double power_log(double power, double val) { return log(val) / log(power); }
template <typename T>
T sqr(T x) {
  return x * x;
}
template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
  for (auto it : v) os << it << " ";
  os << "\n";
  return os;
}
template <typename T, typename H>
inline vector<pair<T, H>> gv_andBiPair(int len) {
  vector<pair<T, H>> a(len);
  for (auto &it : a) {
    cin >> it.first >> it.second;
  }
  return a;
}
template <typename T>
inline set<T> vector_to_set(const vector<T> &vec) {
  set<T> s;
  for (auto &it : vec) s.insert(it);
  return s;
}
const long long md = 998244353;
vector<int> a[maxn];
int dp[6101][6101];
int rec(int l, int r) {
  if (l > r) {
    return 0;
  }
  if (dp[l][r] != -1) {
    return dp[l][r];
  }
  int x = 0;
  for (auto it : a[l]) {
    if (it == r) {
      x = 1;
      break;
    }
  }
  int &ans = dp[l][r];
  ans = max(ans, x + rec(l + 1, r));
  for (auto it : a[l]) {
    if (it >= r) {
      continue;
    }
    ans = max(ans, x + rec(l, it) + rec(it + 1, r));
  }
  return ans;
}
int main() {
  int tests_count = g();
  for (int TEST_CASE = 1; TEST_CASE <= tests_count; ++TEST_CASE) {
    int n = g();
    auto v = gv_andBiPair<int, int>(n);
    set<int> comp;
    for (auto it : v) {
      comp.insert(it.first);
      comp.insert(it.second);
    }
    map<int, int> convert;
    int i = 1;
    for (auto it : comp) {
      convert[it] = i;
      i++;
    }
    for (int j = 0; j < (i + 42); ++j) {
      for (int z = 0; z < (i + 42); ++z) {
        dp[j][z] = -1;
      }
      a[j].clear();
    }
    for (auto it : v) {
      a[convert[it.first]].push_back(convert[it.second]);
    }
    cout << rec(1, i - 1) << "\n";
  }
}
