#include <bits/stdc++.h>
using namespace std;
const int N = 200005;
int n, k;
int a[N], b[N], t[N];
vector<int> z, vec, v;
int res[N], lst[N];
long long ans;
// BIT
int T[N];
void merge(int type, int &x, int y) {
if (type == 0) x = max(x, y); else x += y;
}
void upd(int type, int x, int v) { for (; x > 0; x -= x & -x) merge(type, T[x], v); }
int get(int type, int x) { int res = 0; for (; x < N; x += x & -x) merge(type, res, T[x]); return res; }
int main() {
ios_base::sync_with_stdio(false); cin.tie(0);
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];
z.push_back(t[i]);
vec.push_back(i);
}
sort(z.begin(), z.end());
z.resize(distance(z.begin(), unique(z.begin(), z.end())));
sort(vec.begin(), vec.end(), [&](int x, int y) {
return t[x] < t[y];
});
for (int i = 1; i <= n; ++i) {
if (a[i] > b[i]) swap(a[i], b[i]), res[i] = 1;
v.push_back(i);
}
sort(v.begin(), v.end(), [&](int x, int y) {
return b[x] < b[y];
});
int pt = 0;
for (int i = 0; i < v.size(); ++i) {
while(pt < vec.size() && t[vec[pt]] < b[v[i]]) {
upd(0, lower_bound(z.begin(), z.end(), t[vec[pt]]) - z.begin() + 1, vec[pt]);
++pt;
}
int A = lower_bound(z.begin(), z.end(), a[v[i]]) - z.begin() + 1;
lst[v[i]] = get(0, A);
}
memset(T, 0, sizeof T); // reset BIT
pt = vec.size() - 1;
for (int i = v.size()-1; i >= 0; --i) {
while(pt >= 0 && b[v[i]] <= t[vec[pt]]) {
upd(1, vec[pt], 1);
--pt;
}
if (lst[v[i]] > 0) res[v[i]] = 1;
int cur = get(1, lst[v[i]] + 1);
res[v[i]] ^= (cur & 1);
}
for (int i = 1; i <= n; ++i) {
ans += (res[i] == 0 ? a[i] : b[i]);
}
cout << ans << '\n';
}
