#include <bits/stdc++.h>
using namespace std;
#define X first
#define Y second
#define pb push_back
using ll = long long ;
//#define int long long
using ii = pair < int , int > ;
const int MAX = 200004,M=600004,mod=1e9+7;
const int inf=0x3f3f3f3f;
int K;
vector < int > pr[MAX];
ii a[MAX];
void maxx(int &a,int b){
if(b>a) a=b;
}
int t[MAX];
int F[M];
int val[M];
void upd(int id,int val){
for(;id<M;id+=id&-id) maxx(F[id],val);
}
int get(int id){
int res=0;;
for(;id>0;id-=id&-id) maxx(res,F[id]);
return res;
}
bool ok[MAX];
ii b[MAX];
void UPD(int id){
for(;id>0;id-=id&-id)F[id]++;
}
int GET(int id){
int res=0;
for(;id<M;id+=id&-id)res+=F[id];
return res;
}
bool cmp(ii u,ii v){
return min(u.X,u.Y)>min(v.X,v.Y);
}
int main() {
ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
//freopen("fortune.inp", "r", stdin);//freopen("fortune.out", "w", stdout);
int n,m;
cin>>n>>m;
ll ans=0;
vector < int > vec;
map < int , int > mp;
for(int i=1;i<=n;i++){
cin>>a[i].X>>a[i].Y;
if(a[i].X==a[i].Y) {ans+=a[i].X;i--;n--;continue;}
vec.pb(a[i].X);
vec.pb(a[i].Y);
}
for(int i=1;i<=m;i++){
cin>>t[i];
vec.pb(t[i]);
}
sort(vec.begin(),vec.end());
int pre=0,cnt=0;
for(int u:vec)if(u!=pre){
val[++cnt]=u;
mp[u]=cnt;
pre=u;
}
//cout<<n<<'\n';
for(int i=1;i<=n;i++){
a[i].X=mp[a[i].X];
a[i].Y=mp[a[i].Y];
}
for(int i=1;i<=m;i++){
t[i]=mp[t[i]];
//cout<<t[i]<<'\n';
b[i]=ii(t[i],i);
}
sort(b+1,b+1+m,greater < ii > () );
sort(a+1,a+1+n,cmp );
for(int i=1,x,po=1;i<=n;i++){
bool tt=0;
if(a[i].X>a[i].Y) {swap(a[i].X,a[i].Y);ok[i]=1;}
while(b[po].X>=a[i].X) {
upd(b[po].X,b[po].Y);po++;
}
x=get(a[i].Y-1);
pr[x].pb(i);
//cout<<a[i].X<<' '<<a[i].Y<<' '<<t[x]<<' '<<x<<'\n';
//if(tt)swap(a[i].X,a[i].Y);
}
memset(F,0,sizeof F);
for(int i=m,x;i>0;i--){
for(int u:pr[i]){
x=GET(a[u].Y);
//cout<<val[a[u].X]<<' '<<val[a[u].Y]<<' '<<x<<'\n';
if(x&1) ans+=val[a[u].X];
else ans+=val[a[u].Y];
}
UPD(t[i]);
}
for(int u:pr[0]){
int x=GET(a[u].Y)^ok[u]^1;
//cout<<val[a[u].X]<<' '<<val[a[u].Y]<<' '<<x<<'\n';
if(x&1) ans+=val[a[u].X];
else ans+=val[a[u].Y];
}
cout<<ans;
}
