#include <bits/stdc++.h>
using namespace std;
struct Sparse_Table {
vector<vector<int>> st;
Sparse_Table(const vector<int> &a){
int n = (int)a.size() - 1;
st.resize(__lg(n) + 1);
for (int j = 0; (1 << j) <= n; ++j)
st[j].resize(n + 1);
for (int i = 1; i <= n; ++i)
st[0][i] = a[i];
for (int j = 1; (1 << j) <= n; ++j){
for (int i = 1; i + (1 << j) - 1 <= n; ++i)
st[j][i] = max(st[j - 1][i], st[j - 1][i + (1 << (j - 1))]);
}
}
int query(int l, int r){
int k = __lg(r - l + 1);
return max(st[k][l], st[k][r - (1 << k) + 1]);
}
};
struct Fenwick {
int n;
vector<int> bit;
Fenwick(int n): n(n), bit(n + 1) {}
void update(int i, int x){
for (; i <= n; i += i & -i)
bit[i] += x;
}
int get(int i){
int res = 0;
for (; i; i -= i & -i)
res += bit[i];
return res;
}
int get(int l, int r){
return get(r) - get(l - 1);
}
};
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n, k; cin >> n >> k;
vector<int> a(n), b(n);
for (int i = 0; i < n; ++i)
cin >> a[i] >> b[i];
vector<int> t(k + 1), co;
for (int j = 1; j <= k; ++j){
cin >> t[j];
co.push_back(t[j]);
}
co.push_back(0); // so stuff is 1-indexed or whatever
sort(begin(co), end(co));
co.erase(unique(begin(co), end(co)), end(co));
int m = (int)co.size() - 1;
vector<int> pos(n), cnt(n);
{
vector<int> T(m + 1, 0);
for (int i = 1; i <= k; ++i){
int idx = lower_bound(begin(co), end(co), t[i]) - begin(co);
T[idx] = i;
}
Sparse_Table st(T);
for (int i = 0; i < n; ++i){
int u = a[i], v = b[i];
if (u > v) swap(u, v);
int l = lower_bound(begin(co), end(co), u) - begin(co);
int r = lower_bound(begin(co), end(co), v) - begin(co) - 1;
if (l <= r) pos[i] = st.query(l, r);
}
}
{
vector<vector<int>> qr(k + 1);
for (int i = 0; i < n; ++i) if (pos[i] < k)
qr[pos[i] + 1].push_back(i);
Fenwick bit(m);
for (int j = k; j >= 1; --j){
int idx = lower_bound(begin(co), end(co), t[j]) - begin(co);
bit.update(idx, 1);
for (int i : qr[j]){
idx = lower_bound(begin(co), end(co), max(a[i], b[i])) - begin(co);
cnt[i] = bit.get(idx, m);
}
}
}
long long res = 0;
for (int i = 0; i < n; ++i){
// this mf exists => top side is always max
if (pos[i] > 0){
if (a[i] < b[i]) swap(a[i], b[i]);
}
// all t[j] >= max(a[i], b[i]) later => always a flip
if (cnt[i] & 1) swap(a[i], b[i]);
res += a[i];
}
cout << res << '\n';
}
