#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<long, long>;
using vi = vector<int>;
using vl = vector<long long>;
#define pb push_back
#define F first
#define S second
#define sz(a) int((a).size())
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define sum(a) ( accumulate((a).begin(), (a).end(), 0LL))
#define lowb(a, x) ( lower_bound((a).begin(), (a).end(), (x)) - (a).begin())
#define uppb(a, x) ( upper_bound((a).begin(), (a).end(), (x)) - (a).begin())
#define yes cout << "YES" << endl
#define no cout << "NO" << endl
void fastIO() { ios_base::sync_with_stdio(false); cin.tie(NULL); }
const ll mod = 1e9 + 7;
struct WaveletTree {
vi b;
int lo, hi;
WaveletTree *l, *r;
WaveletTree (int *i, int *j, int x, int y) {
lo = x, hi = y;
if (lo == hi) return;
int mid = (lo + hi) / 2;
b.pb(0);
for (auto it = i; it != j; it++) {
b.pb(b.back() + (*it <= mid));
}
auto k = stable_partition(i, j, [mid] (int x) {return x <= mid;});
if (i < k) l = new WaveletTree(i, k, lo, mid);
if (k < j) r = new WaveletTree(k, j, mid + 1, hi);
}
int query(int l, int r, int k) {
if (l > r || k < lo) return 0;
if (hi <= k) return r - l + 1;
int lb = b[l - 1], rb = b[r];
return this->l->query(lb + 1, rb, k) + this->r->query(l - lb, r - rb, k);
}
int query(int l, int r, int x, int y) {
l++; r++;
if (y < x) return 0;
return query(l, r, y) - query(l, r, x - 1);
}
};
void solve() {
int n, k;
cin >> n >> k;
vi a(n), b(n);
for (int i = 0; i < n; i++) {
cin >> a[i] >> b[i];
}
int t[k];
for (int &u: t) cin >> u;
vi c;
for (int u: a) c.pb(u);
for (int u: b) c.pb(u);
for (int u: t) c.pb(u);
sort(all(c));
c.resize(unique(all(c)) - c.begin());
for (int &u: a) {
u = lowb(c, u);
}
for (int &u: b) {
u = lowb(c, u);
}
for (int &u: t) {
u = lowb(c, u);
}
WaveletTree T(t, t + k, 0, 6e5);
ll ans = 0;
for (int i = 0; i < n; i++) {
int x = T.query(0, k - 1, min(a[i], b[i]), max(a[i], b[i]) - 1);
if (x == 0) {
if (T.query(0, k - 1, max(a[i], b[i]), 1e9) % 2) {
ans += c[b[i]];
} else {
ans += c[a[i]];
}
} else {
int l = -1, r = k - 1;
while (l + 1 < r) {
int m = (l + r) / 2;
if (T.query(0, m, min(a[i], b[i]), max(a[i], b[i]) - 1) == x) {
r = m;
} else {
l = m;
}
}
if (T.query(r + 1, k - 1, max(a[i], b[i]), 1e9) % 2) {
ans += c[min(a[i], b[i])];
} else {
ans += c[max(a[i], b[i])];
}
}
}
cout << ans;
}
int main() {
fastIO();
cout << setprecision(15) << fixed;
int t = 1;
// cin >> t;
while (t--) solve();
return 0;
}
