#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int MN = 200010;
int N, K;
struct Query {
int a, b, id;
bool operator <(const Query &i) const {
return max(a, b) < max(i.a, i.b);
}
};
Query query[MN];
int T[MN], ans[MN];
vector<pii> ord;
struct BIT {
vector<int> tree;
void init() {
tree = vector<int>(4 * K);
build(0, K - 1, 1);
}
void build(int l, int r, int n) {
if(l == r) {
tree[n] = T[l];
return;
}
int m = (l + r)>>1;
build(l, m, 2*n);
build(m + 1, r, 2*n + 1);
tree[n] = max(tree[2*n], tree[2*n + 1]);
}
void upd(int idx, int val, int l, int r, int n) {
if(idx < l || r < idx) return;
if(l == r) {
tree[n] = val;
return;
}
int m = (l + r)>>1;
upd(idx, val, l, m, 2*n);
upd(idx, val, m + 1, r, 2*n + 1);
tree[n] = max(tree[2*n], tree[2*n + 1]);
}
int kquer(int k, int l, int r, int n) {
if(tree[n] < k) return -1;
if(l == r) return l;
int m = (l + r)>>1;
if(tree[2*n + 1] >= k) return kquer(k, m + 1, r, 2*n + 1);
else return kquer(k, l, m, 2*n);
}
} bit;
struct Fenwick {
vector<int> tree;
void init() {
tree = vector<int>(K + 1, 0);
}
void upd(int idx, int val) {
for(int i = idx + 1; i <= K; i += (i & -i)) tree[i] += val;
}
int quer(int a) {
int ret = 0;
for(int i = a + 1; i >= 1; i -= (i & -i)) ret += tree[i];
return ret;
}
int quer(int a, int b) {
return quer(b) - quer(a - 1);
}
} fwt;
int main() {
scanf("%d %d", &N, &K);
for(int i = 0; i < N; i++) {
int a, b; scanf("%d %d", &a, &b);
query[i] = {a, b, i};
}
for(int i = 0; i < K; i++) {
scanf("%d", &T[i]);
}
for(int i = 0; i < K; i++) ord.push_back({ T[i], i });
sort(query, query + N);
sort(ord.begin(), ord.end());
bit.init();
fwt.init();
ll ans = 0;
int pos = K - 1;
for(int i = N - 1; i >= 0; i--) {
while(pos >= 0 && ord[pos].first >= max(query[i].a, query[i].b)) {
fwt.upd(ord[pos].second, 1);
bit.upd(ord[pos].second, -1, 0, K - 1, 1);
pos--;
}
int a = min(query[i].a, query[i].b);
int t = bit.kquer(a, 0, K - 1, 1);
int d = fwt.quer(t + 1, K - 1);
if(t == -1) {
if(d & 1) ans += query[i].b;
else ans += query[i].a;
}
else {
if(d & 1) ans += min(query[i].a, query[i].b);
else ans += max(query[i].a, query[i].b);
}
}
printf("%lld", ans);
}
