#include <bits/stdc++.h>
using namespace std;
using ll = long long;
template <class T>
struct segtree {
int n;
T e;
T (*f)(T, T);
vector<T> s;
segtree(int n, T (*f)(T, T), T e):
n(n), e(e), f(f), s(2 * n, e) {
}
segtree(const vector<T> &a, T (*f)(T, T), T e):
segtree(a.size(), f, e) {
for (int i = 2 * n - 1; i; i--) {
s[i] = i < n ? f(s[i * 2], s[i * 2 + 1]) : a[i - n];
}
}
void set(int i, const T &v) {
for (i += n, s[i] = v; i /= 2;) {
s[i] = f(s[i * 2], s[i * 2 + 1]);
}
}
T qry(int l, int r) {
T u(e), v(e);
for (l += n, r += n; l < r; l /= 2, r /= 2) {
if (l & 1) u = f(u, s[l++]);
if (r & 1) v = f(s[--r], v);
}
return f(u, v);
}
};
int f(int x, int y) {
return max(x, y);
}
int g(int x, int y) {
return x ^ y;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int N, K;
cin >> N >> K;
vector<int> A(N), B(N), T(K);
for (int i = 0; i < N; i++) cin >> A[i] >> B[i];
for (int i = 0; i < K; i++) cin >> T[i];
vector<int> v;
v.insert(v.end(), A.begin(), A.end());
v.insert(v.end(), B.begin(), B.end());
v.insert(v.end(), T.begin(), T.end());
sort(v.begin(), v.end());
v.erase(unique(v.begin(), v.end()), v.end());
for (auto &i : A) i = lower_bound(v.begin(), v.end(), i) - v.begin();
for (auto &i : B) i = lower_bound(v.begin(), v.end(), i) - v.begin();
for (auto &i : T) i = lower_bound(v.begin(), v.end(), i) - v.begin();
int M = v.size();
segtree<int> s1(M, f, -1);
for (int i = 0; i < K; i++) s1.set(T[i], i);
vector<int> a(N);
vector<vector<int>> b(K);
for (int i = 0; i < N; i++) {
a[i] = s1.qry(min(A[i], B[i]), max(A[i], B[i]));
if (a[i] != -1) b[a[i]].push_back(i);
}
ll ans = 0;
segtree<int> s2(M, g, 0);
for (int i = K - 1; i >= 0; i--) {
for (int j : b[i]) {
ans += s2.qry(max(A[j], B[j]), M) ? v[min(A[j], B[j])] : v[max(A[j], B[j])];
}
s2.set(T[i], s2.qry(T[i], T[i] + 1) ^ 1);
}
for (int i = 0; i < N; i++) {
if (a[i] == -1) {
ans += s2.qry(A[i], M) ? v[B[i]] : v[A[i]];
}
}
cout << ans;
return 6/22;
}
