#include <iostream>
#include <map>
#include <vector>
#include <climits>
#include <stack>
#include <string>
#include <queue>
#include <algorithm>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <cmath>
#include <cctype>
#include <bitset>
#include <iomanip>
#include <cstring>
#include <numeric>
using namespace std;
#define int long long
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define fi first
#define se second
int q;
vector<int> ft;
int qq(int i){
int sum=0;
for (;i;i-=i&(-i))sum+=ft[i];
return sum;
}
void up(int i, int val){
for (;i<=q;i+=i&(-i))ft[i]+=val;
}
struct node{
int s, e, m, 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 up(int ind, int nv){
if (s==e)val=nv;
else{
if (ind<=m)l->up(ind, nv);
else r->up(ind, nv);
val = max(l->val, r->val);
}
}
int query(int left, int right){
if (s==left && e==right)return val;
if (right<=m)return l->query(left, right);
else if (left>m)return r->query(left, right);
else return max(l->query(left, m), r->query(m+1, right));
}
}*st;
bool custom(pii a, pii b){
return max(a.fi, a.se)<max(b.fi, b.se);
}
int32_t main(){
int n, ans=0;
cin>>n>>q;
vector<pii> vect(n), query(q);
ft.resize(q+1, 0);
st = new node(0, q-1);
for (int i=0; i<n; ++i)cin>>vect[i].fi>>vect[i].se;
for (int i=0; i<q; ++i)cin>>query[i].fi, query[i].se=i+1, up(i+1, 1);
sort(query.begin(), query.end());
sort(vect.begin(), vect.end(), custom);
for (int i=0; i<q; ++i)st->up(i, query[i].se);
for (int i=0, p=0; i<n; ++i){
while (p<q&&query[p].fi<max(vect[i].fi, vect[i].se))up(query[p].se, -1), ++p;
if (!p||query[p-1].fi<min(vect[i].fi, vect[i].se))ans+=((q-p)%2?vect[i].se:vect[i].fi);
else{
int low=-1, high=p;
while (low+1<high){
int mid=(low+high)/2;
if (query[mid].fi>=min(vect[i].fi, vect[i].se))high=mid;
else low=mid;
}
ans+=((qq(q)-qq(st->query(high, p-1)))%2?min(vect[i].fi, vect[i].se):max(vect[i].fi, vect[i].se));
}
}
cout<<ans;
}
