#include<iostream>
#include<algorithm>
#include<set>
#include<utility>
#include<queue>

using namespace std;

int main(){
  priority_queue<pair<int, int>> que;
  multiset<int> bag;
  int N, K;
  long long int ans = 0;
  cin >> N >> K;
  for(int i = 0; i<N; i++){
    int tmp1, tmp2;
    scanf("%d %d", &tmp1, &tmp2);
    que.push(make_pair(tmp2, tmp1));
  }
  for(int i = 0; i<K; i++){
    int tmp;
    scanf("%d", &tmp);
    bag.insert(tmp);
  }
  while(que.size() && bag.size()){
    pair<int,int> tmp = que.top();
    que.pop();
    auto p = bag.lower_bound(tmp.second);
    if(p != bag.end()){
      ans+= tmp.first;
      bag.erase(p);
    }
  }
  cout<< ans<<endl;
}

#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
typedef struct _jewel { int m, v; } j;
std::vector<j> jewel;
std::multiset<int> c;

int main() {
	int n, k;
	std::cin >> n >> k;
	for (int i = 0; i < n; i++) {
		j t;
		std::cin >> t.m >> t.v;
		jewel.push_back(t);
	}
	std::sort(jewel.begin(), jewel.end(), [](j a, j b) {return a.v < b.v; });

	for (int i = 0; i < k; i++) {
		int t;
		std::cin >> t;
		c.insert(t);
	}

	long long int res = 0;
	while (jewel.size() && c.size()) {
		j t = jewel[jewel.size() - 1];
		jewel.pop_back();

		std::multiset<int>::iterator it = c.lower_bound(t.m);
		if (it != c.end()) {
			res += t.v;
			c.erase(it);
		}
	}

	std::cout << res;
	return 0;
}