#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//#include "bits_stdc++.h"
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define lb lower_bound
#define ub upper_bound
#define input(x) scanf("%lld", &x);
#define input2(x, y) scanf("%lld%lld", &x, &y);
#define input3(x, y, z) scanf("%lld%lld%lld", &x, &y, &z);
#define input4(x, y, z, a) scanf("%lld%lld%lld%lld", &x, &y, &z, &a);
#define print(x, y) printf("%lld%c", x, y);
#define show(x) cerr << #x << " is " << x << endl;
#define show2(x,y) cerr << #x << " is " << x << " " << #y << " is " << y << endl;
#define show3(x,y,z) cerr << #x << " is " << x << " " << #y << " is " << y << " " << #z << " is " << z << endl;
#define discretize(x) sort(x.begin(), x.end()); x.erase(unique(x.begin(), x.end()), x.end());
using namespace std;
//using namespace __gnu_pbds;
//#define ordered_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
//#define ordered_multiset tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update>
typedef long long ll;
typedef long double ld;
typedef pair<ld, ll> pd;
typedef pair<string, ll> psl;
typedef pair<ll, ll> pi;
typedef pair<ll, pi> pii;
ll n, k, x, y,ans = 0;
ll const INF = 1e13;
vector<ll> activated;
bool compare(pii a, pii b)
{
return activated[a.f]<activated[b.f];
}
struct node{
int s, e, m;
ll val, summ;
ll lazy;
node *l, *r;
node (int S, int E)
{
s = S, e = E, m = (s+e)/2;
val = 0;
lazy = 0;
summ = 0;
l=r=nullptr;
}
void create()
{
if(s != e && l==nullptr)
{
l = new node(s, m);
r = new node(m+1, e);
}
}
void propogate()
{
if (lazy==0) return;
create();
val+=lazy;
summ+=lazy*(e-s+1);
if (s != e){
l->lazy+=lazy;
r->lazy+=lazy;
}
lazy=0;
}
void update(int S, int E, ll V)
{
propogate();
if(s==S && e==E) lazy += V;
else{
create();
propogate();
if(E <= m) l->update(S, E, V);
else if (m < S) r->update(S, E, V);
else l->update(S, m, V),r->update(m+1, E, V);
l->propogate(),r->propogate();
val = max(l->val, r->val);
summ = l-> summ+ r->summ;
}
}
ll maxquery(int S, int E)
{
propogate();
if(s == S && e == E) return val;
create();
if(E <= m) return l->maxquery(S, E);
else if(S >= m+1) return r->maxquery(S, E);
else return max(l->maxquery(S, m), r->maxquery(m+1, E));
}
ll sumquery(int S, int E)
{
propogate();
if(s == S && e == E) return summ;
create();
if(E <= m) return l->sumquery(S, E);
else if(S >= m+1) return r->sumquery(S, E);
else return l->sumquery(S, m) + r->sumquery(m+1, E);
}
} *root;
int main()
{
ll n, q, x, y,ans = 0;
input2(n, q);
vector<pii> card;
vector<pi> card2;
vector<ll> queries(q+1);
vector<ll> dum;
activated.resize(n);
for (ll i=0; i<n; ++i)
{
input2(x, y);
if (x==y) {ans+=x; continue;} // does not matter
if (x<y) {dum.pb(i);}
else {swap(x,y);}
card.pb(mp(i, mp(x,y)));
card2.pb(mp(y, i));
ans+=y;
}
sort(card2.begin(), card2.end());
vector<ll> ind(n);
for (ll i=0; i<card.size(); ++i) ind[card2[i].s] = i;
n = card.size();
root = new node(1, 1e9+5);
map<ll,ll> m;
for (ll i=1; i<=q; ++i)
{
input(queries[i]);
m[queries[i]] = i;
}
for (pi u: m) {root->update(u.f, u.f, u.s);}
for (ll i=0; i<n; ++i) {activated[card[i].f] = root->maxquery(card[i].s.f, card[i].s.s-1); }
sort(card.begin(), card.end(), compare);
delete root;
root = new node(0, n+5);
ll slide = -1;
for (ll u: dum) root->update(ind[u], ind[u], 1);
for (ll i=1; i<=q; ++i)
{
ll in = ub(card2.begin(), card2.end(), mp(queries[i], INF))-card2.begin();
if (in>=1) root->update(0, in-1, 1);
while (slide+1<n && activated[card[slide+1].f]<=i)
{
slide++;
if (activated[card[slide].f]==0) continue;
if (root->sumquery(ind[card[slide].f], ind[card[slide].f])%2)
{
root->update(ind[card[slide].f], ind[card[slide].f], 1);
}
}
}
for (ll i=0; i<n; ++i)
{
if (root->sumquery(ind[card[i].f], ind[card[i].f])%2) ans+=card[i].s.f - card[i].s.s;
}
print(ans, '\n');
return 0;
}
