#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ari2 = array<int, 2>;
using ari3 = array<int, 3>;
#define vt vector
#define size(x) (int((x).size()))
#define all(x) begin(x), end(x)
#define REP(a, b, c, d) for (int a = (b); (d) > 0 ? a <= (c) : a >= (c); a += (d))
#define FOR(a, b, c) REP(a, b, c, 1)
#define ROF(a, b, c) REP(a, b, c, -1)
constexpr int mxN = 200001, INF = 0x3f3f3f3f;
int N, K, SZ;
struct Node {
int val;
Node *lft, *rht;
Node() : val(0), lft(nullptr), rht(nullptr) {}
Node(int v) : val(v), lft(nullptr), rht(nullptr) {}
Node(Node *v) : val(v->val), rht(v->rht), lft(v->lft) {}
Node(Node *l, Node *r) {
lft = l, rht = r;
val = (l ? l->val : 0) + (r ? r->val : 0);
}
};
Node *sts[mxN];
Node *build(int tl = 0, int tr = K) {
if (tl == tr)
return new Node();
int tm = tl + tr >> 1;
return new Node(build(tl, tm), build(tm+1, tr));
}
Node *upd(Node *n, int p, int v, int tl = 0, int tr = K) {
if (tl == tr)
return new Node(n->val + v);
int tm = tl + tr >> 1;
if (p <= tm)
return new Node(upd(n->lft, p, v, tl, tm), n->rht);
return new Node(n->lft, upd(n->rht, p, v, tm+1, tr));
}
int walk(Node *na, Node *nb, int tl = 0, int tr = K) {
if (tl == tr)
return tl;
int tm = tl + tr >> 1;
if (na->rht->val == nb->rht->val)
return walk(na->lft, nb->lft, tl, tm);
return walk(na->rht, nb->rht, tm+1, tr);
}
int qry(Node *n, int ql, int qr, int tl = 0, int tr = K) {
if (tl > qr || tr < ql || qr < ql)
return 0;
if (ql <= tl && tr <= qr)
return n->val;
int tm = tl + tr >> 1;
return qry(n->lft, ql, qr, tl, tm) + qry(n->rht, ql, qr, tm+1, tr);
}
signed main() {
#ifndef DEBUG
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
#endif
cin >> N >> K;
int A[N], B[N];
FOR(i, 0, N-1)
cin >> A[i] >> B[i];
int T[K];
vt<int> cmp;
FOR(i, 0, K-1)
cin >> T[i], cmp.push_back(T[i]);
sort(all(cmp));
cmp.erase(unique(all(cmp)), end(cmp));
cmp.push_back(INF);
auto cind = [&](int i) {
return lower_bound(all(cmp), i) - begin(cmp);
};
vt<int> inds[SZ=size(cmp)];
FOR(i, 0, K-1)
inds[cind(T[i])].push_back(i);
vt<ari3> qrys[SZ];
FOR(i, 0, N-1)
qrys[cind(min(A[i], B[i]))].push_back({cind(max(A[i], B[i])), A[i], B[i]});
ll ans = 0;
sts[SZ-1] = new Node(build());
ROF(i, SZ-1, 0) {
if (i < SZ-1)
sts[i] = new Node(sts[i+1]);
for (int j : inds[i])
sts[i] = new Node(upd(sts[i], j, 1));
for (auto [j, a, b] : qrys[i]) {
if (i == j)
ans += qry(sts[i], 0, K) & 1 ? b : a;
else {
int k = walk(sts[j], sts[i]);
int v = qry(sts[j], k+1, K);
ans += (a < b) ^ (v & 1) ? b : a;
}
}
}
cout << ans << '\n';
}
