#include<stdio.h>

#include<vector>

#include<map>

#include<algorithm>

using namespace std;

const int N = ;

pair<int, int>edge[N];

vector<int> vec;

map<int, int> mp;

struct SegmentTree

{

    int l, r;

    bool mk;

    bool lazy;

};

SegmentTree tree[N << ];

void build(int l, int r, int k)

{

    tree[k].l = l, tree[k].r = r, tree[k].mk = false, tree[k].lazy = false;

    if(l== r)

        return;

    int mid = (l + r) >> ;

    build(l, mid, k<<);

    build(mid+, r, k<<|);

}

bool query(int l, int r, int k)

{

    if(tree[k].mk)

        return true;

    if(tree[k].l >= l && tree[k].r <= r)

        return tree[k].mk;

    bool a = true, b = true;

    if(tree[k<<].r >= l)

        a = query(l, r, k<<);

    if(tree[k<<|].l <= r)

        b = query(l, r, k<<|);

    return (a && b);

}

void updata(int l, int r, int k)

{

    if(tree[k].l >= l && tree[k].r <= r)

    {

        tree[k].mk = true;

        tree[k].lazy = true;

        return;

    }

    if(tree[k].lazy)

    {

        tree[k<<].lazy = tree[k<<|].lazy = true;

        tree[k].lazy = false;

        tree[k<<].mk = tree[k<<|].mk = true;

    }

    if(tree[k<<].r >= l)

        updata(l, r, k<<);

    if(tree[k<<|].l <= r)

        updata(l, r, k<<|);

    tree[k].mk = (tree[k<<].mk && tree[k<<|].mk);

}

void solve()

{

    int n;

    scanf("%d", &n);

    vec.clear();

    for(int i=; i<n; ++ i)

    {

        scanf("%d%d", &edge[i].first, &edge[i].second);

        vec.push_back(edge[i].first);

        vec.push_back(edge[i].second);

    }

    sort(vec.begin(), vec.end());

    vec.erase(unique(vec.begin(), vec.end()), vec.end());

    mp.clear();

    int s = ;

    for(int i=; i<vec.size(); ++ i)

    {

        mp[vec[i]] = s;

        if(i != vec.size() - )

        {

            if(vec[i+] == vec[i] + )

                s ++;

            else

                s += ;

        }

    }

    build(, s, );

    int ans = ;

    for(int i=n-; i>=; -- i)

    {

        int l = mp[edge[i].first], r = mp[edge[i].second];

        if(query(l, r, ) == false)

        {

            ans ++;

            updata(l, r, );

        }

    }

    printf("%d\n", ans);

}

int main()

{

    int t;

    scanf("%d", &t);

    while(t --)

        solve();

    return ;

}