#include<iostream>
#include<string>
#include<vector>
#include<algorithm>

using namespace std;

void solve()
{
	int n, m;
	cin >> n >> m;
	vector<int> g(n + 1), close(n + 1), val(n + 1);
	vector<vector<int>> open(n + 1);
	for (int i = 0; i < m; i++)
	{
		int l, r;
		cin >> l >> r;
		--l;
		open[l].push_back(r);
		close[r]++;
	}
	int max_val = -1, cur = 0;
	for (int i = 0; i <= n; i++)
	{
		for (auto x : open[i])
		{
			cur++;
			max_val = max(max_val, x);
		}
		cur -= close[i];
		val[i] = cur;
		g[i] = max(max_val, i + 1);
	}
	vector<int> dp(n + 1, -int(1e9));
	dp[0] = 0;
	for (int i = 0; i < n; i++)
	{
		dp[i + 1] = max(dp[i + 1], dp[i]);
		dp[g[i]] = max(dp[g[i]], dp[i] + val[i]);
	}
	cout << dp[n] << "\n";
}

int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int t;
	cin >> t;
	for (int i = 0; i < t; i++) solve();
}