#include <bits/stdc++.h>
#define lsb(x) (x & (-x))
#define ll long long
#define ull unsigned long long
// 217
// 44
using namespace std;
struct SegTree {
struct Node {
int cnt;
int mx;
};
vector <Node> aint;
int n;
inline void init(int _n) {
n = _n;
aint.resize(4 * n + 1, {0, 0});
}
inline void refresh(int nod) {
aint[nod].cnt = aint[2 * nod].cnt + aint[2 * nod + 1].cnt;
aint[nod].mx = max(aint[2 * nod].mx, aint[2 * nod + 1].mx);
}
void update_cnt(int nod, int left, int right, int pos) {
if(left == right) {
aint[nod].cnt++;
}
else {
int mid = (left + right) / 2;
if(pos <= mid) update_cnt(2 * nod, left, mid, pos);
else update_cnt(2 * nod + 1, mid + 1, right, pos);
refresh(nod);
}
}
void update_mx(int nod, int left, int right, int pos, int mx) {
if(left == right) {
aint[nod].mx = mx;
}
else {
int mid = (left + right) / 2;
if(pos <= mid) update_mx(2 * nod, left, mid, pos, mx);
else update_mx(2 * nod + 1, mid + 1, right, pos, mx);
refresh(nod);
}
}
int query_mx(int nod, int left, int right, int val) {
if(aint[nod].mx < val) {
return 0;
}
if(left == right) {
return left;
}
else {
int mid = (left + right) / 2;
if(aint[2 * nod + 1].mx >= val) return query_mx(2 * nod + 1, mid + 1, right, val);
return query_mx(2 * nod, left, mid, val);
}
}
int query_cnt(int nod, int left, int right, int l, int r) {
if(l > r) return 0;
if(l <= left && right <= r) {
return aint[nod].cnt;
}
else {
int mid = (left + right) / 2;
int ans = 0;
if(l <= mid) ans += query_cnt(2 * nod, left, mid, l, r);
if(mid < r) ans += query_cnt(2 * nod + 1, mid + 1, right, l, r);
return ans;
}
}
};
int main() {
//ifstream cin("A.in");
//ofstream cout("A.out");
int i, n, m;
ios::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
cin >> n >> m;
vector <int> ord(n + 1), a(n + 1), b(n + 1);
for(i = 1; i <= n; i++) {
cin >> a[i] >> b[i];
ord[i] = i;
}
sort(next(ord.begin()), ord.end(), [&](const int &x, const int &y) {
return max(a[x], b[x]) > max(a[y], b[y]);
});
vector < pair <int, int> > t(m + 1);
for(i = 1; i <= m; i++) {
cin >> t[i].first;
t[i].second = i;
}
sort(next(t.begin()), t.end(), [&](const pair <int, int> &a, const pair <int, int> &b) {
return a.first > b.first;
});
SegTree st; st.init(m);
for(i = 1; i <= m; i++) {
st.update_mx(1, 1, m, t[i].second, t[i].first);
}
ll ans = 0;
int pos = 1;
for(i = 1; i <= n; i++) {
while(pos <= m && t[pos].first >= max(a[ord[i]], b[ord[i]])) {
st.update_cnt(1, 1, m, t[pos].second);
st.update_mx(1, 1, m, t[pos].second, 0);
pos++;
}
int p = st.query_mx(1, 1, m, min(a[ord[i]], b[ord[i]]));
if(p != 0) {
if(a[ord[i]] < b[ord[i]]) {
swap(a[ord[i]], b[ord[i]]);
}
}
if(st.query_cnt(1, 1, m, p + 1, m) % 2) {
ans += b[ord[i]];
}
else {
ans += a[ord[i]];
}
}
cout << ans;
//cin.close();
//cout.close();
return 0;
}
