#include <set>
#include <queue>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
#define N (400010)
#define inf (0x3f3f3f3f)
#define INF (0x3f3f3f3f3f3f3f3fll)
#define LL long long
int T, n, ret[N];
struct Segment {
    int l, r;
    friend bool operator< (const Segment& a, const Segment& b) {
        return a.r > b.r;
    }
} Seg[N];

inline int read() {
    int x = 0, f = 1; char ch = getchar();
    while (ch < '0' || ch > '9')
        ch == '-' ? f = -1, ch = getchar() : ch = getchar();
    while (ch >= '0' && ch <= '9')
        x = (x << 1) + (x << 3) + (ch ^ 48), ch = getchar();
    return x * f;
}

bool cmp(const Segment& a, const Segment& b) {
    return a.l < b.l;
}

int main() {
    T = read();
    while (T--) {
        n = read();

        int cnt = 0;
        for (int i = 1; i <= n; ++i) {
            Seg[i].l = read(), Seg[i].r = read();
            ret[++cnt] = Seg[i].l;
            ret[++cnt] = Seg[i].r;
        } 
        sort(ret + 1, ret + cnt + 1);
        for (int i = 1, tmp = cnt; i <= tmp; ++i)
            if (ret[i] - ret[i - 1] > 1) ret[++cnt] = ret[i - 1] + 1;
        sort(ret + 1, ret + cnt + 1);
        // for (int i = 1; i <= cnt; ++i) printf("%d ", ret[i]); puts("");
        cnt = unique(ret + 1, ret + cnt + 1) - ret - 1;
        // printf("%d\n", cnt);
        // for (int i = 1; i <= cnt; ++i) printf("%d ", ret[i]); puts("");
        sort(Seg + 1, Seg + n + 1, cmp);
        for (int i = 1; i <= n; ++i) {
            Seg[i].l = lower_bound(ret + 1, ret + cnt + 1, Seg[i].l) - ret;
            Seg[i].r = lower_bound(ret + 1, ret + cnt + 1, Seg[i].r) - ret;
            // printf("    SEG %d %d %d\n", i, Seg[i].l, Seg[i].r);
        }

        int idx = 1, ans = 0;
        priority_queue<Segment> q;
        for (int i = 1; i <= cnt; ++i) {
            while (q.size() && q.top().r < i) q.pop();
            while (idx <= n && Seg[idx].l >= i) q.push(Seg[idx]), idx++;
            if (q.size()) ++ans, q.pop();
        }
        printf("%d\n", ans);
    }
    return 0;
}