#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> ii;
const int N = 200005;
int n, k, a[N], b[N], t[N];
int lg2[N], rmq[20][N];
int bit[N], res[N];
vector<ii> go, query[N];
int get(int l, int r) {
int k = lg2[r - l + 1];
return max(rmq[k][l], rmq[k][r - (1 << k) + 1]);
}
void upd(int x) {
for (x; x > 0; x -= x & -x) bit[x]++;
}
int get(int x) {
int ret = 0; for (x; x <= k; x += x & -x) ret += bit[x]; return ret;
}
int main() {
ios::sync_with_stdio(false);
cin >> n >> k;
for (int i = 1; i <= n; ++i) {
cin >> a[i] >> b[i];
}
for (int i = 1; i <= k; ++i) {
cin >> t[i], go.push_back(ii(t[i], i));
}
sort(go.begin(), go.end());
for (int i = 2; i <= k; ++i) lg2[i] = lg2[i >> 1] + 1;
for (int i = 0; i < k; ++i) rmq[0][i] = go[i].second;
for (int i = 1; i < 18; ++i) {
for (int j = 0; j + (1 << i) - 1 < k; ++j) {
rmq[i][j] = max(rmq[i - 1][j], rmq[i - 1][j + (1 << (i - 1))]);
}
}
for (int i = 1; i <= n; ++i) {
int l = min(a[i], b[i]), r = max(a[i], b[i]);
l = lower_bound(go.begin(), go.end(), ii(l, 0)) - go.begin();
r = lower_bound(go.begin(), go.end(), ii(r, 0)) - go.begin() - 1;
int tmp = 0;
if (l <= r) {
tmp = get(l, r);
if (a[i] < b[i]) swap(a[i], b[i]);
}
query[r + 1].push_back(ii(i, tmp + 1));
}
for (int i = k - 1; i >= 0; --i) {
upd(go[i].second);
for (auto j : query[i]) res[j.first] = get(j.second) & 1;
}
long long sum = 0;
for (int i = 1; i <= n; ++i) {
sum += (!res[i] ? a[i] : b[i]);
}
cout << sum << '\n';
}
