#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pi pair<int, int>
#define pii pair<int, pair<int, int> >
#define fi first
#define se second
int n,m,q;
int ft[200005];
void upd(int p, int v){
for(;p<=m;p+=(p & -p))ft[p] += v;
}
int query(int p){
int sum = 0;
for(;p;p-=(p & -p))sum += ft[p];
return sum;
}
pi A[200005];
bool cmp(pi a, pi b){
return max(a.fi, a.se) < max(b.fi, b.se);
}
pi Q[200005];
void solve(){
cin >> n >> m;
for(int i=1;i<=n;i++)cin >> A[i].fi >> A[i].se;
sort(A+1, A+n+1, cmp);
for(int i=1;i<=m;i++)cin >> Q[i].fi, Q[i].se = i, upd(i, 1);
sort(Q+1, Q+m+1);
int in = 1, cur = 0;
Q[0].fi = -1e9;
int ans = 0;
for(int i=1;i<=n;i++){
while(in <= m && Q[in].fi < max(A[i].fi, A[i].se))cur = max(cur, Q[in].se), upd(Q[in].se, -1), in++;
int tmp;
if(Q[in-1].fi < min(A[i].fi, A[i].se)){
tmp = query(m);
ans += (tmp%2 ? A[i].se : A[i].fi);
}
else {
tmp = query(m) - query(cur);
ans += (tmp%2 ? min(A[i].fi, A[i].se) : max(A[i].fi, A[i].se));
}
//cout << ans << ' ' << A[i].fi << ' ' << A[i].se << '\n';
}
cout << ans;
}
main(){
ios::sync_with_stdio(0);cin.tie(0);
int t = 1;
//cin >> t;
while(t--){
solve();
}
}
