#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define MAXN (1000005)
bool cmp(pair<ll,ll> a,pair<ll,ll> b){
return max(a.first,a.second) > max(b.first,b.second);
}
ll fw[MAXN];
void upd(int x,ll nval) {
for(;x<MAXN;x+=x&(-x)) fw[x]+=nval;
}
ll query(int x) {
ll res = 0;
for(;x;x-=x&(-x)) res += fw[x];
return res;
}
ll sum(int a,int b) {
return query(b) - query(a-1);
}
struct node{
int s, e, m;
int val;
node *l, *r;
node (int S, int E){
s = S, e = E, m = (s+e)/2;
val = 0;
if(s != e){
l = new node(s, m);
r = new node(m+1, e);
}
}
void update(int X, int V){
if(s == e) val = V;
else{
if(X <= m) l->update(X, V);
else r->update(X, V);
val = max(l->val,r->val);
}
}
int query(int S, int E){
if(s == S && e == E) return val;
else if(E <= m) return l->query(S, E);
else if(S >= m+1) return r->query(S, E);
else return max(l->query(S, m),r->query(m+1, E));
}
} *root;
int main() {
ios_base::sync_with_stdio(false);cin.tie(0);
ll N,K;
cin>>N>>K;
root = new node(0,K - 1);
vector<pair<ll,ll> > c;
vector<pair<ll,ll> > q;
for(ll i = 0;i < N;i++){
ll a,b;
cin>>a>>b;
c.push_back({a,b});
}
for(ll i = 0;i < K;i++){
ll t;
cin>>t;
q.push_back({t,i});
}
sort(c.begin(),c.end(),cmp);
sort(q.begin(),q.end());
for(ll i = 0;i < K;i++){
root -> update(i,q[i].second);
}
ll index = K - 1;
ll ans = 0;
for(auto u : c){
ll a = u.first;
ll b = u.second;
while(index >= 0 && q[index].first >= max(a,b)){
upd(q[index].second + 1,1);
index--;
}
ll low = lower_bound(q.begin(),q.end(),make_pair(min(a,b),0ll)) - q.begin();
ll high = lower_bound(q.begin(),q.end(),make_pair(max(a,b),0ll)) - q.begin();
ll s = -1;
if(low <= high - 1){
s = root -> query(low,high - 1);
}
ll num = sum(max(1ll,s + 1),K);
if(s == -1 && b > a) num++;
if(num % 2 == 0) ans += max(a,b);
else ans += min(a,b);
}
cout<<ans<<'\n';
}
