#include<cstdio>
#include<utility>
#include<vector>
#include<algorithm>
using namespace std;

int main()
{
	int n, m, ans = 0;
	vector<pair<int, int>> v;
	scanf("%d%d", &n, &m);
	v.resize(n+m);
	for(int i = 0; i < n + m; ++i) scanf("%d%d", &v[i].first, &v[i].second);
	sort(v.begin(), v.end() ,[](const pair<int, int> &a, const pair<int, int> &b) {
		return a.first - a.second < b.first - b.second;
	}); 
	for(int i = 0; i < n; ++i) ans += v[i].first;
	for(int i = 0; i < m; ++i) ans += v[n + i].second;
	printf("%d\n", ans);
	return 0;
}