#include <stdio.h>
#include <algorithm>
#include <vector>
using namespace std;
const int Z = 1 << 18;
vector<int> G[Z * 2];
int N, K, A[200200], B[200200], T[200200];
int cnt(int x, int l, int r)
{
auto &v = G[x];
return upper_bound(v.begin(), v.end(), r) - lower_bound(v.begin(), v.end(), l);
}
int cnt(int x, int y, int l, int r)
{
int res = 0;
x += Z; y += Z;
while (x < y) {
if (x & 1) res += cnt(x++, l, r);
if (~y & 1) res += cnt(y--, l, r);
x /= 2; y /= 2;
} if (x == y) res += cnt(x, l, r);
return res;
}
int get(int l, int r)
{
int x = 1;
while (x < Z) {
x *= 2; x++;
if (cnt(x, l, r) == 0) x--;
}
return x - Z;
}
int main()
{
scanf("%d %d", &N, &K);
for (int i = 0; i < N; i++) scanf("%d %d", &A[i], &B[i]);
for (int j = 0; j < K; j++) {
scanf("%d", &T[j]);
G[j + Z].push_back(T[j]);
}
for (int i = Z - 1; i >= 1; i--) {
vector<int> &a = G[i * 2];
vector<int> &b = G[i * 2 + 1];
vector<int> &c = G[i]; c.reserve(a.size() + b.size());
int p = 0, q = 0;
while (p < a.size() && q < b.size()) {
if (a[p] < b[q]) c.push_back(a[p++]);
else c.push_back(b[q++]);
}
while (p < a.size()) c.push_back(a[p++]);
while (q < b.size()) c.push_back(b[q++]);
}
long long ans = 0;
for (int i = 0; i < N; i++) {
int p = 0;
if (min(A[i], B[i]) != max(A[i], B[i])) {
p = get(min(A[i], B[i]), max(A[i], B[i]) - 1);
}
int q = cnt(p, K-1, max(A[i], B[i]), 0x7fffffff);
if (p && A[i] < B[i]) swap(A[i], B[i]);
if (q & 1) swap(A[i], B[i]);
ans += A[i];
}
printf("%lld\n", ans);
return 0;
}
