//cre: khanh nguyen
// luoi code qua -_-
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define F first
#define S second
#define pb push_back
#define pii pair<int, int>
const int N = 2e5 + 5;
struct SegTree {
int n;
vector<int> st;
SegTree() {}
SegTree(int n) : n(n) {
st.resize(4 * n + 5);
}
void update(int id, int l, int r, int i, int x) {
if (l == r) {
st[id] = max(st[id], x);
return;
}
int mid = (l + r) / 2;
if (i <= mid) update(id * 2, l, mid, i, x);
else update(id * 2 + 1, mid + 1, r, i, x);
st[id] = max(st[id * 2], st[id * 2 + 1]);
}
int get(int id, int l, int r, int u, int v) {
if (u > v) return 0;
if (l > v || r < u) return 0;
if (u <= l && r <= v) {
return st[id];
}
int mid = (l + r) / 2;
return max(get(id * 2, l, mid, u, v), get(id * 2 + 1, mid + 1, r, u, v));
}
} st;
struct BIT {
int n;
vector<int> bit;
BIT() {}
BIT(int n) : n(n) {
bit.resize(n + 3);
}
void update(int id, int val) {
for (int i = id; i <= n; i += (i & -i)) bit[i] += val;
}
int get(int id) {
int ret = 0;
for (int i = id; i; i -= (i & -i)) ret += bit[i];
return ret;
}
} bit;
int n, m;
pii a[N];
int c[N];
vector<int> cmp;
int t[N];
int res[N];
int sz;
struct Event {
int x, sign, id;
};
vector<Event> ev[N];
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m;
for (int i = 1; i <= n; i++) {
cin >> a[i].F >> a[i].S;
cmp.pb(a[i].F);
cmp.pb(a[i].S);
}
for (int i = 1; i <= m; i++) {
cin >> c[i];
cmp.pb(c[i]);
}
sort(cmp.begin(), cmp.end());
cmp.erase(unique(cmp.begin(), cmp.end()), cmp.end());
sz = cmp.size();
st = SegTree(sz);
int sz = cmp.size();
for (int i = 1; i <= m; i++) {
int id = upper_bound(cmp.begin(), cmp.end(), c[i]) - cmp.begin();
st.update(1, 1, sz, id, i);
}
for (int i = 1; i <= n; i++) {
int ida, idb;
ida = upper_bound(cmp.begin(), cmp.end(), a[i].F) - cmp.begin();
idb = upper_bound(cmp.begin(), cmp.end(), a[i].S) - cmp.begin();
if (ida > idb) swap(ida, idb);
t[i] = st.get(1, 1, sz, ida, idb - 1);
//cout << t[i] << ' ';
ev[t[i]].pb({idb, -1, i});
ev[m].pb({idb, 1, i});
} // cout << '\n';
bit = BIT(sz);
for (int i = 1; i <= m; i++) {
int id = upper_bound(cmp.begin(), cmp.end(), c[i]) - cmp.begin();
bit.update(id, 1);
for (auto it : ev[i]) {
res[it.id] += (bit.get(sz) - bit.get(it.x - 1)) * it.sign;
}
}
int sum=0;
for (int i = 1; i <= n; i++) {
int ans;
if (t[i]) {
ans = max(a[i].F, a[i].S);
if (res[i] & 1) ans = min(a[i].F, a[i].S);
}
else {
ans = a[i].F;
if (res[i] & 1) ans = a[i].S;
}
sum+=ans;
}
cout << sum;
}
