#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int maxn = 2000 + 5, inf = 0x3f3f3f3f; 

int dp_result(int n, int m, int *boy, int *girl)
{
	int dp[maxn + maxn];
	memset(dp, 0x3f, sizeof(dp));
	dp[0] = girl[0]; dp[1] = boy[0];
	for(int i = 1; i < n + m; ++i)
	{
		for(int j = min(n, i + 1); j > 0; --j)
		{
			dp[j] = min(dp[j] + girl[i], dp[j - 1] + boy[i]);
			dp[j] = min(dp[j], inf);
		}
		dp[0] += girl[i];
	}
	return dp[n];
}

int main()
{
	int n, m;
	int boy[maxn + maxn], girl[maxn + maxn];
	scanf("%d%d", &n, &m);
	for(int i = 0; i < n + m; ++i)
	{
		scanf("%d%d", &boy[i], &girl[i]);
	}
	printf("%d\n", dp_result(n, m, boy, girl));
	return 0;
}