//Huyduocdithitp
#include <bits/stdc++.h>
typedef long long ll;
#define pii pair<ll, ll>
#define MP make_pair
#define fi first
#define se second
#define TASK "connect"
#define faster ios_base::sync_with_stdio(false);cin.tie(NULL);
#define N 1000005
#define LOG 18
#define endl '\n'
using namespace std;
ll n, m, s, kq[N];
pii a[N];
pii t[N];
vector<ll> ns;
bool cmp(pii a, pii b) {
return max(a.fi, a.se) > max(b.fi, b.se);
}
ll st[4 * N], bit[N];
void upd(ll u, ll v) {
ll idx = u;
while (idx <= s) {
bit[idx] += v;
idx += idx & (-idx);
}
}
ll get(ll u) {
ll idx = u, ans = 0;
while (idx > 0) {
ans += bit[idx];
idx -= idx & (-idx);
}
return ans;
}
void update(ll id, ll l, ll r, ll i, ll v) {
if (i > r || i < l) return;
if (l == r) {
if (v == 0) st[id] = 0;
else st[id] = max(st[id], v);
return;
}
ll mid = (l + r) / 2;
update(id * 2, l, mid, i, v);
update(id * 2 + 1, mid + 1, r, i, v);
st[id] = max(st[id * 2], st[id * 2 + 1]);
}
ll get(ll id, ll l, ll r, ll L, ll R) {
if (l > R || r < L) return 0;
if (L <= l && r <= R) return st[id];
ll mid = (l + r) / 2;
return max(get(id * 2, l, mid, L, R), get(id * 2 + 1, mid + 1, r, L, R));
}
void pre() {
s = ns.size();
sort(ns.begin(), ns.end());
ns.resize(unique(ns.begin(), ns.end()) - ns.begin());
for (int i = 1; i <= n; i ++) {
a[i].fi = lower_bound(ns.begin(), ns.end(), a[i].fi) - ns.begin() + 1;
a[i].se = lower_bound(ns.begin(), ns.end(), a[i].se) - ns.begin() + 1;
}
for (int i = 1; i <= m; i ++) {
t[i].fi = lower_bound(ns.begin(), ns.end(), t[i].fi) - ns.begin() + 1;
update(1, 1, s, t[i].fi, i);
//cout << " len " << t[i].fi << " " << i << endl;
t[i].se = i;
}
sort(t + 1, t + 1 + m);
}
void solve() {
ll ans = 0;
ll cur = m;
for (int i = 1; i <= n; i ++) {
//cout << a[i].fi << " " << a[i].se << endl;
}
for (int i = 1; i <= m; i ++) {
//cout << t[i].fi << " ";
}
//cout << endl;
for (int i = 1; i <= n; i ++) {
bool flag = 0;
if (a[i].fi > a[i].se) {
flag = 1;
swap(a[i].fi, a[i].se);
}
while (cur >= 1 && t[cur].fi >= max(a[i].fi, a[i].se)) {
update(1, 1, s, t[cur].fi, 0);
//cout << " t cur ve 0 " << t[cur].fi << " " << st[1] << endl;
upd(t[cur].se, 1);
//cout << "upd cur " << t[cur].se << endl;
cur -- ;
}
if (a[i].fi == a[i].se) {
ans += ns[a[i].fi - 1];
continue;
}
ll id = get(1, 1, s, a[i].fi, a[i].se - 1);
ll dem = get(s) - get(id);
//cout << i << " id " << id << " flag " << flag << " d " << dem << " a " << ans << endl;
if (id == 0 && flag == 1) {
dem ++ ;
if (dem % 2 == 1) {
ans += ns[a[i].se - 1];
}
else {
ans += ns[a[i].fi - 1];
}
continue;
}
if (a[i].fi < a[i].se && id > 0) swap(a[i].fi, a[i].se);
//cout << "_ " << a[i].fi << " " << a[i].se << endl;
if (dem % 2 == 0) {
ans += ns[a[i].fi - 1];
}
else {
ans += ns[a[i].se - 1];
}
}
cout << ans;
}
signed main(void) {
faster;
cin >> n >> m;
for (int i = 1; i <= n; i ++) {
cin >> a[i].fi >> a[i].se;
ns.push_back(a[i].fi);
ns.push_back(a[i].se);
}
sort(a + 1, a + 1 + n, cmp);
for (int i = 1; i <= m; i ++) {
cin >> t[i].fi;
ns.push_back(t[i].fi);
}
pre();
solve();
return 0;
}
