#include <bits/stdc++.h>   using namespace std;   vector<vector<short>> g;   vector<vector<short>> dp;   short rec(int l, int r) {     if (l > r) return 0;     if (dp[l][r] != -1) return dp[l][r];     short whole = binary_search(begin(g[l]), end(g[l]), r);     short ret = whole + rec(l + 1, r);     for (auto p : g[l]) {       if (p >= r) break;       int val = whole + rec(l, p) + rec(p + 1, r);       if (val > ret) {         ret = val;       }     }     return dp[l][r] = ret;   }   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     int tc;     cin >> tc;     while (tc--) {       int n;       cin >> n;       vector<pair<int, int>> arr(n);       vector<int> val;       for (auto& pp : arr) {         cin >> pp.first >> pp.second;         val.push_back(pp.first);         val.push_back(pp.second);       }       sort(begin(val), end(val));       val.erase(unique(begin(val), end(val)), end(val));       int m = int(val.size());       g = vector<vector<short>>(m);       vector<short> cnt(m + 1, 0);       for (auto& pp : arr) {         pp.first = lower_bound(begin(val), end(val), pp.first) - begin(val);         pp.second = lower_bound(begin(val), end(val), pp.second) - begin(val);         cnt[pp.first]++;       }       for (int i = 0; i < m; i++) {         g[i].resize(cnt[i]);       }       fill(begin(cnt), end(cnt), 0);       for (auto& pp : arr) {         g[pp.first][cnt[pp.first]++] = pp.second;       }       cnt.clear();       val.clear();       for (auto& row : g) {         sort(begin(row), end(row));         row.erase(unique(begin(row), end(row)), end(row));       }       dp = vector<vector<short>>(m, vector<short>(m, -1));       cout << rec(0, m - 1) <<   n ;     }     return (0);   }   