#include <bits/stdc++.h>
using namespace std;
#define maxn 200010
#define pii pair<int, int>
#define ppi pair<pii, pii>
#define mp make_pair
int N, K;
int a[maxn];
int b[maxn];
int t[maxn];
vector<ppi> events;
int ans[maxn];
int seg[maxn*4]; //store the minimum value
int ct = 0;
int inf = 1234567890;
#define ll long long
int qu(int qs, int qe, int ss, int se, int si) {
if (qs > qe || ss > se) return inf;
if (qs > se || qe < ss) return inf;
if (qs <= ss && se <= qe) return seg[si];
int mid = (ss+se)/2;
return min(qu(qs, qe, ss, mid, si*2+1),
qu(qs, qe, mid+1, se, si*2+2));
}
int query(int qs, int qe) {
return qu(qs, qe, 0, K, 0);
}
void up(int spot, int val, int ss, int se, int si) {
if (ss == se) {
seg[si] = min(seg[si], val);
return;
}
int mid = (ss+se)/2;
if (spot <= mid) up(spot, val, ss, mid, si*2+1);
else up(spot, val, mid+1, se, si*2+2);
seg[si] = min(seg[si*2+1], seg[si*2+2]);
}
void update(int spot, int val) {
up(spot, val, 0, K, 0);
}
int walkdown(int goal, int ss, int se, int si) {
//wnat last index s.t. the value is < it
if (ss == se) return ss;
int mid = (ss+se)/2;
if (seg[si*2+2] < goal) {
//something is good enough in the left, go there
return walkdown(goal, mid+1, se, si*2+2);
}
else return walkdown(goal, ss, mid, si*2+1);
}
int BIT[maxn];
int bq(int val) {
int res = 0;
while (val > 0) {
res += BIT[val];
val -= val & (-val);
}
return res;
}
int bquery(int lo, int hi) {
lo++;
hi++;
return bq(hi) - bq(lo-1);
}
void bupdate(int spot) {
spot++;
while (spot < maxn) {
BIT[spot]++;
spot += spot & (-spot);
}
}
map<int, int> deco;
map<int, int> goback;
int main() {
fill(seg, seg+maxn*4, inf);
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> N >> K;
set<int> vals;
for (int i = 0; i < N; i++) {
cin >> a[i] >> b[i];
vals.insert(a[i]);
vals.insert(b[i]);
}
vector<int> vvec;
for (int vv : vals) {
goback[ct] = vv;
deco[vv] = ct++;
vvec.push_back(vv);
}
for (int i = 0; i < N; i++) {
a[i] = deco[a[i]];
b[i] = deco[b[i]];
events.push_back(mp(mp(min(a[i], b[i]), 0), mp(max(a[i], b[i]), i)));
}
for (int i = 0; i < K; i++) {
cin >> t[i];
int indo = upper_bound(vvec.begin(), vvec.end(), t[i]) -
vvec.begin()-1;
t[i] = indo;
events.push_back(mp(mp(t[i], 1), mp(-1, i)));
}
sort(events.begin(), events.end());
reverse(events.begin(), events.end());
for (int i = 0; i < events.size(); i++) {
int tp = events[i].first.second;
if (tp == 0) {
//this is one of the queries
//(lol we don't need indices anymore)
int ai = events[i].first.first;
int bi = events[i].second.first;
int indo = events[i].second.second;
ai = a[indo];
bi = b[indo];
// cout << "got indo: " << indo << endl;
if (ai == bi) {
ans[indo] = ai;
continue;
}
bool flip = ai <= bi;
int mx = max(ai, bi);
int nx = -1;
if (query(0, K) >= mx) {
//no last value
}
else {
nx = walkdown(mx, 0, K, 0);
}
int avals = bquery(nx+1, K);
if (nx == -1 && ai != mx) avals++; //think this works
avals %= 2;
if (ai == mx) {
if (avals) ans[indo] = bi;
else ans[indo] = ai;
}
else {
if (avals) ans[indo] = ai;
else ans[indo] = bi;
}
}
else {
update(events[i].second.second, events[i].first.first);
bupdate(events[i].second.second);
}
}
ll fans = 0;
// cout << "answers: " << endl;
for (int i = 0; i < N; i++) {
// cout << ans[i] << " ";
// cout << " " << i << ": " << a[i] << " " << b[i] << " : " << ans[i] << endl;
fans += goback[ans[i]] + 0LL;
}
// cout << endl;
cout << fans << '\n';
cout.flush();
}
