#include <bits/stdc++.h>
#define ll long long
#define ull unsigned ll
#define pb push_back
#define pa pair<int, int>
#define pall pair<ll, int>
#define fi first
#define se second
#define TASK "test"
#define Size(x) (int) x.size()
#define all(x) x.begin(), x.end()
using namespace std;
template<typename T1, typename T2> bool mini (T1 &a, T2 b) {if(a > b) a = b; else return 0; return 1;}
template<typename T1, typename T2> bool maxi (T1 &a, T2 b) {if(a < b) a = b; else return 0; return 1;}
const int MOD = 1e9 + 7;
const int LOG = 20;
const int maxn = 6e5 + 7;
const ll oo = 1e18 + 69;
int n, k, t[maxn], last[maxn];
pa a[maxn];
bool swapped[maxn];
vector<int> val, ev[2][maxn];
bool cmp(pa &a, pa &b) {
return a.se < b.se;
}
struct ST {
struct node {
int mx;
friend node operator + (node a, const node &b) {
maxi(a.mx, b.mx);
return a;
}
};
node st[4 * maxn];
void update(int id, int l, int r, int pos, int val) {
if(pos < l || pos > r) return;
if(l == r) {
maxi(st[id].mx, val);
return;
}
int mid = l + r >> 1;
update(id << 1, l, mid, pos, val);
update(id << 1 | 1, mid + 1, r, pos, val);
st[id] = st[id << 1] + st[id << 1 | 1];
}
node get(int id, int l, int r, int u, int v) {
if(r < u || l > v) return {0};
if(u <= l && r <= v) return st[id];
int mid = l + r >> 1;
return get(id << 1, l, mid, u, v) + get(id << 1 | 1, mid + 1, r, u, v);
}
} st;
int id(int x) {
return lower_bound(all(val), x) - val.begin() + 1;
}
struct BIT {
int bit[maxn];
void update(int x, int val) {
for(; x <= k; x += x&-x) bit[x] += val;
}
int get(int x) {
int ans = 0;
for(; x; x -= x&-x) ans += bit[x];
return ans;
}
} bit;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
//freopen(TASK".inp", "r", stdin);
//freopen(TASK".out", "w", stdout);
cin>>n>>k;
for(int i = 1; i <= n; i++) {
cin>>a[i].fi>>a[i].se;
val.pb(a[i].fi);
val.pb(a[i].se);
if(a[i].fi > a[i].se) {
swap(a[i].fi, a[i].se);
swapped[i] = 1;
}
}
for(int i = 1; i <= k; i++) {
cin>>t[i];
val.pb(t[i]);
}
sort(all(val));
val.erase(unique(all(val)), val.end());
for(int i = 1; i <= k; i++) {
int idd = id(t[i]);
ev[0][idd].pb(i);
st.update(1, 1, Size(val), idd, i);
}
for(int i = 1; i <= n; i++) {
int l = id(a[i].fi);
int r = id(a[i].se) - 1;
if(l <= r) last[i] = st.get(1, 1, Size(val), l, r).mx;
ev[1][r + 1].pb(i);
}
ll ans = 0;
for(int i = Size(val); i >= 1; i--) {
for(auto j:ev[0][i]) bit.update(j, 1);
for(auto j:ev[1][i]) {
int cnt = bit.get(k) - bit.get(last[j]);
if(last[j] != 0) swap(a[j].fi, a[j].se);
if(cnt & 1) swap(a[j].fi, a[j].se);
if(last[j] == 0 && swapped[j]) swap(a[j].fi, a[j].se);
ans += a[j].fi;
}
}
cout<<ans;
return 0;
}
