#include<bits/stdc++.h>
using namespace std;
#define task "fortunetelling2"
#define rep(i,a,b) for(int i=(a);i<=(b);++i)
#define per(i,a,b) for(int i=(a);i>=(b);--i)
#define ll long long
#define pii pair<int,int>
#define fi first
#define se second
#define lwb lower_bound
#define upb upper_bound
#define pb push_back
#define eb emplace_back
#define all(v) (v).begin(),(v).end()
const int maxn = 2e5;
const int MAX = 6e5;
int n,k;
int a[maxn+5],b[maxn+5];
int t[maxn+5];
int f[MAX+5][21];
int maxk;
int last[maxn+5];
int ord[maxn+5];
int bit[MAX+5];
int tmp[MAX+5];
int id=0;
void init(){
rep(i,1,id) bit[i]=0;
}
void upd(int u,int val){
while(u>0){
bit[u]+=val;
u-=u&(-u);
}
}
int getSuf(int u){
int res=0;
while(u<=id){
res+=bit[u];
u+=u&(-u);
}
return res;
}
int getMax(int u,int v){
int k=log2(v-u+1);
return max(f[u][k],f[v-(1<<k)+1][k]);
}
bool cmp(int u,int v){
return last[u]>last[v];
}
int main(){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> k;
rep(i,1,n) cin >> a[i] >> b[i];
rep(i,1,k) cin >> t[i];
rep(i,1,n){
tmp[++id]=a[i];
tmp[++id]=b[i];
}
rep(i,1,k) tmp[++id]=t[i];
sort(tmp+1,tmp+id+1);
rep(i,1,n){
a[i]=lwb(tmp+1,tmp+id+1,a[i])-tmp;
b[i]=lwb(tmp+1,tmp+id+1,b[i])-tmp;
}
rep(i,1,k){
t[i]=lwb(tmp+1,tmp+id+1,t[i])-tmp;
f[t[i]][0]=max(f[t[i]][0],i);
}
maxk = log2(id);
rep(k,1,maxk){
rep(i,1,id-(1<<k)+1){
f[i][k]=max(f[i][k-1],f[i+(1<<(k-1))][k-1]);
}
}
rep(i,1,n){
if(a[i]==b[i]) last[i]=0;
else last[i]=getMax(min(a[i],b[i]),max(a[i],b[i])-1);
}
rep(i,1,n) ord[i]=i;
sort(ord+1,ord+n+1,cmp);
init();
int cur=k;
ll ans=0;
rep(i,1,n){
int u=ord[i];
while(cur>last[u]){
upd(t[cur],1);
--cur;
}
if(last[u]>0){
if(a[u]<b[u]) swap(a[u],b[u]);
}
if(getSuf(max(a[u],b[u]))%2) swap(a[u],b[u]);
ans+=tmp[a[u]];
}
cout << ans;
return 0;
}
