#include <cstdio>
#include <algorithm>
using namespace std;

int casenum, n;
pair<int,int> a[100005];

int main() {
	scanf("%d", &casenum);
	while (casenum--) {
		scanf("%d", &n);
		for (int i = 0; i < n; ++i) {
			scanf("%d%d", &a[i].first, &a[i].second);
			a[i].second--;
		}
		sort(a, a+n);
		int ans = 0, last = -2;
		for (int i = 0; i < n; ++i) {
			if (last + 1 >= a[i].first) last = min(last+1, a[i].second);
			else ans++, last = a[i].second;
		}
		printf("%d\n", ans-1);
	}
}