[RE] (https://www.luogu.com.cn/record/106355122)

#include <bits/stdc++.h>
using namespace std;
#pragma GCC target("avx2")
#define pi pair<int,int>
#define mk make_pair
#define x first
#define y second
const int N=1e5+5;
int n,m1,m2,ans;
int anx[N],any[N];
pi a[N],b[N];
inline int work(pi *t,int *ans,int m) {  priority_queue<pi,vector<pi>,greater<pi> > wt;

    priority_queue<int,vector<int>,greater<int> > q;

    for(int i=1;i<=n;++i)   q.push(i);

    for(int i=1;i<=m;++i) {

        while(!wt.empty()&&t[i].x>=wt.top().x)  q.push(wt.top().y),wt.pop();

        if(q.empty())   continue;

        int v=q.top();  q.pop();

        ++ans[v],wt.push(mk(t[i].y,v));

    }

    for(int i=1;i<=n;++i)   ans[i]+=ans[i-1];

}

signed main() {

    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);

    cin>>n>>m1>>m2;

    for(int i=1;i<=m1;++i)  cin>>a[i].x>>a[i].y;

    for(int i=1;i<=m2;++i)  cin>>b[i].x>>b[i].y;

    sort(a+1,a+m1+1),sort(b+1,b+m2+1);

    work(a,anx,m1),work(b,any,m2);

    for(int i=0;i<=n;++i)   ans=max(ans,anx[i]+any[n-i]);

    cout<<ans;

    return 0;

}