#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(x) x.begin(), x.end()
using pint = pair<int, int>;
template <int (*COMB)(int, int)>
struct St {
int n;
vector<int> st;
void init(int n) { st.resize((this->n = n) << 1); }
void update(int i, int a, int b) {
for ((st[i += n] *= a) += b; i >>= 1;) st[i] = COMB(st[i << 1], st[i << 1 | 1]);
}
int query(int l, int r) {
int ret = 0;
for (l += n, r += n; l < r; l >>= 1, r >>= 1) {
if (l & 1) ret = COMB(ret, st[l++]);
if (r & 1) ret = COMB(ret, st[--r]);
}
return ret;
}
};
St<[] (int a, int b) { return max(a, b); }> mx;
St<[] (int a, int b) { return a + b; }> sum;
int main() {
int n, q;
cin >> n >> q;
int A[n], B[n];
for (int i = n; i--;) cin >> A[i] >> B[i];
int ops[q];
for (int &op: ops) cin >> op;
vector<int> cc(ops, ops + q);
sort(all(cc));
cc.erase(unique(all(cc)), cc.end());
mx.init(cc.size());
auto idx = [&] (int i) { return lower_bound(all(cc), i) - cc.begin(); };
for (int i = 0; i < q; ++i) mx.update(idx(ops[i]), 0, i + 1);
vector<int> queries[q + 1];
for (int i = n; i--;) {
int j = mx.query(idx(min(A[i], B[i])), idx(max(A[i], B[i])));
if (j and A[i] < B[i]) swap(A[i], B[i]);
queries[j].emplace_back(i);
}
sum.init(cc.size());
ll ans = 0;
for (int i = q; i >= 0; --i) {
if (i < q) sum.update(idx(ops[i]), 1, 1);
for (int j: queries[i]) ans += sum.query(idx(max(A[j], B[j])), cc.size()) & 1 ? B[j] : A[j];
}
cout << ans << endl;
}
