Sunscreen

#include <iostream>
#include <string>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <algorithm>
#include <vector>
#include <queue>
#include <deque>
#include <map>
#define range(i,a,b) for(int i=a;i<=b;++i)
#define LL long long
#define rerange(i,a,b) for(int i=a;i>=b;--i)
#define fill(arr,tmp) memset(arr,tmp,sizeof(arr))
using namespace std;
int C,L;
pair<int,int> fuck[2505],you[2505];
priority_queue <int, vector<int>, greater<int> > q;
bool cmp(pair<int,int>a,pair<int,int>b){
    return a.first<b.first;
}
void init() {
    cin >> C >> L;
    range(i, 0, C - 1)cin >> fuck[i].first >> fuck[i].second;
    range(i, 0, L - 1)cin >> you[i].first >> you[i].second;
    sort(fuck,fuck+C,cmp);
    sort(you,you+L,cmp);
}
void solve(){
    int j=0,ans=0;
    range(i,0,L-1){
        while(j<C&&fuck[j].first<=you[i].first){
            q.push(fuck[j].second);
            ++j;
        }
        while(!q.empty()&&you[i].second){
            int tmp=q.top();
            q.pop();
            if(tmp<you[i].first)continue;
            ++ans;
            you[i].second--;
        }
    }
    cout<<ans<<endl;
}
int main() {
    init();
    solve();
    return 0;
}