#include<bits/stdc++.h>
using namespace std;
#define pii pair<int,int>
#define fi first
#define se second
const int N = 4e5+5;
int n,k,b[N],l[N],r[N],bits[N],state[N];
pii a[N];
vector<int>nen,kaori[N],emilia[N];
void update(int u){
while(u <= nen.size()){
bits[u]++;
u += u & (-u);
}
}
int get(int u){
int sum = 0;
while(u > 0){
sum += bits[u];
u -= u & (-u);
}
return sum;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> k;
for(int i = 1; i <= n; i++){
cin >> a[i].fi >> a[i].se;
if(a[i].fi > a[i].se){
swap(a[i].fi,a[i].se);
state[i] = 1;
}
nen.push_back(a[i].fi);
nen.push_back(a[i].se);
}
sort(nen.begin(),nen.end());
nen.erase(unique(nen.begin(),nen.end()),nen.end());
for(int i = 1; i <= k; i++) cin >> b[i];
for(int i = 1; i <= k; i++) b[i] = upper_bound(nen.begin(),nen.end(),b[i])-nen.begin();
for(int i = 1; i <= n; i++){
a[i].fi = lower_bound(nen.begin(),nen.end(),a[i].fi)-nen.begin()+1;
a[i].se = lower_bound(nen.begin(),nen.end(),a[i].se)-nen.begin()+1;
r[i] = k;
}
while(true){
int cnt = 0;
for(int i = 1; i <= k; i++) kaori[i].clear();
for(int i = 1; i <= n; i++){
if(l[i] < r[i]){
kaori[(l[i]+r[i]+1)/2].push_back(i);
cnt++;
}
}
if(cnt == 0) break;
for(int i = 1; i <= nen.size(); i++) bits[i] = 0;
for(int i = k; i >= 1; i--){
update(b[i]);
for(int u: kaori[i]){
if(get(a[u].se-1) > get(a[u].fi-1)) l[u] = i;
else r[u] = i-1;
}
}
}
for(int i = 1; i <= nen.size(); i++) bits[i] = 0;
long long ans = 0;
for(int i = 1; i <= n; i++){
if(l[i] == k) ans += a[i].se;
else emilia[l[i]+1].push_back(i);
}
for(int i = k; i >= 1; i--){
update(b[i]);
for(int u: emilia[i]){
int chancode = k-i+1-get(a[u].se-1);
if(l[u] == 0){
chancode += state[u];
if(chancode % 2 == 0) ans += nen[a[u].fi-1];
else ans += nen[a[u].se-1];
}
else{
if(chancode % 2 == 1) ans += nen[a[u].fi-1];
else ans += nen[a[u].se-1];
}
}
}
cout << ans;
}
