#include "bits/stdc++.h"
using namespace std;
#define fi first
#define se second
#define pii pair<int,int>
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
#define pb push_back
#define ll long long
#define mp make_pair
#define cerr if(0)cerr
const int N = 2e5+5;
const int inf = 1e9;
int n,m;
struct Node{
int a,b,id;
bool operator <(const Node &o)const{
return max(a,b) > max(o.a,o.b);
}
void print(){
cerr<<a<<" "<<b<<" "<<"\n";
}
}s[N];
pii c[N];
struct MinMax{
pii a[N];
int tb[N][25];
void build(){
for(int i=1;i<=m;i++) a[i]=c[i];
sort(a+1,a+m+1);
for(int i=1;i<=m;i++) cerr<<a[i].fi<<" "<<a[i].se<<"\n";
for(int i=m;i>=1;i--){
tb[i][0]= a[i].se;
for(int j=1;i+(1<<j)-1<=m;j++){
tb[i][j]= max(tb[i][j-1], tb[i+(1<<(j-1))][j-1]);
}
}
cerr<<"\n";
}
int get(int l, int r){
int j= __lg(r-l+1);
return max(tb[l][j], tb[r-(1<<j)+1][j]);
}
int query(int lo, int hi){
int l = lower_bound(a+1,a+m+1,mp(lo,0))-a;
int r= lower_bound(a+1,a+m+1,mp(hi+1,0))-1-a;
cerr<<l<<" "<<r<<"\n";
if(l>r) return 0;
return get(l,r);
}
}stnx;
struct BIT{
int bit[N];
void update(int i){
for(;i>0;i-=i&-i) bit[i]+=1;
}
int get(int i){
int ans =0;
for(;i<=m;i+=i&-i) ans+=bit[i];
return ans;
}
}bit;
int ans[N];
signed main(){
ios_base::sync_with_stdio(NULL);
cin.tie(NULL);
// if(fopen("TASK.INP", "r")){
// freopen("TASK.INP", "r", stdin);
// freopen("TASK.OUT", "w", stdout);
// }
cin>>n>>m;
for(int i=1;i<=n;i++){
int a,b; cin>>a>>b;
s[i]={a,b,i};
}
sort(s+1,s+n+1);
for(int i=1;i<=m;i++) cin>>c[i].fi, c[i].se =i;
stnx.build();
sort(c+1,c+m+1,greater<pii>());
// for(int i=1;i<=n;i++) s[i].print();
// cerr<<"\n";
// for(int i=1;i<=m;i++) cerr<<c[i]<<" ";
int pt =1;
for(int i=1;i<=n;i++){
int mn = min(s[i].a,s[i].b), mx = max(s[i].a,s[i].b);
while(pt<=m&&c[pt].fi>=mx) {
bit.update(c[pt++].se);
}
if(s[i].a==s[i].b){
ans[s[i].id] = s[i].a;
continue;
}
int pos = stnx.query(mn, mx-1);
cerr<<s[i].a<<" "<<s[i].b<<" "<<pos<<"\n";
int ope = bit.get(pos+1) %2;
if(pos==0) ans[s[i].id] = ope? s[i].b : s[i].a;
else ans[s[i].id]= ope? mn: mx;
}
ll res=0;
for(int i=1;i<=n;i++) res+=ans[i];
cout<<res;
}
