#include
     
      using namespace std;struct Node{    int M, V;    friend bool operator < (const Node n1, const Node n2){        return n1.V < n2.V;    }};bool cmp(Node n1, Node n2){    return n1.M < n2.M;}int main(){    int N, K;    while(cin >> N >> K){        Node arr[N];        for(int i = 0; i < N; i++)cin >> arr[i].M >> arr[i].V;        sort(arr, arr+N, cmp);        long long pkg[K];        for(int i = 0; i < K; i++) cin >> pkg[i];        sort(pkg, pkg+K);                priority_queue
      
        pq;        long long ans = 0;        int index = 0;        for(int i = 0; i < K; i++){            while(index < N && arr[index].M <= pkg[i]){                pq.push(arr[index]);                index++;            }            if(!pq.empty()){                Node n = pq.top();                pq.pop();                ans += n.V;                }        }        cout << ans << endl;    }}