#include #include <bits/stdc++.h> using namespace std; #define int long long

const int maxn=2510; pair<int,int>cows[maxn]; int n,m; signed main(){ cin>>n>>m; for(int i=0;i<n;i++)cin>>cows[i].first>>cows[i].second; sort(cows,cows+n);

map<int,int>spfs;
for(int i=0;i<m;i++){
    int spf,cover;
    cin>>spf>>cover;
    spfs[spf]+=cover;
}

int res=0;

//spfs[0]=spfs[1001]=n;

for(int i=n-1;i>=0;i--){
    
    auto cow=cows[i];
    auto it=spfs.upper_bound(cow.second);
    it--;
    if(it->first>=cow.first && it->first<=cow.second){
        res++;
        if(--it->second==0)spfs.erase(it);
    }
}

cout<<res<<endl;

}