#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define pb push_back
#define ff first
#define ss second
const int A = 1e9;
struct ST{
struct node{
node *l, *r;
int s;
node(){
l = r = 0;
s = 0;
}
};
node *rt;
void init(){
rt = new node();
}
void add(node *v, int tl, int tr, int x){
if (tl == tr){
v -> s += 1;
return;
}
int tm = (tl + tr) / 2;
if (x <= tm){
if (!(v -> l)) v -> l = new node();
add(v -> l, tl, tm, x);
}
else {
if (!(v -> r)) v -> r = new node();
add(v -> r, tm + 1, tr, x);
}
v -> s = 0;
if (v -> l) v -> s += v -> l -> s;
if (v -> r) v -> s += v -> r -> s;
}
void add(int x){
add(rt, 1, A, x);
}
int get(node *v, int tl, int tr, int l, int r){
if (l > tr || r < tl) return 0;
if (l <= tl && tr <= r) return v -> s;
int tm = (tl + tr) / 2, out = 0;
if (v -> l) out += get(v -> l, tl, tm, l, r);
if (v -> r) out += get(v -> r, tm + 1, tr, l, r);
return out;
}
int get(int x){
return get(rt, 1, A, x, A);
}
};
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, k; cin>>n>>k;
vector<int> a(n + 1), b(n + 1);
for (int i = 1; i <= n; i++){
cin>>a[i]>>b[i];
}
vector<int> t(k + 1);
vector<pii> all = {{}};
for (int i = 1; i <= k; i++){
cin>>t[i];
all.pb({t[i], i});
}
sort(all.begin() + 1, all.end());
vector<int> f(k + 1), p(k + 1);
for (int i = 1; i <= k; i++){
f[i] = all[i].ff;
p[i] = all[i].ss;
}
auto get = [&](int l, int r){
if (l > r) return 0;
int out = 0;
for (int i = l; i <= r; i++){
out = max(out, p[i]);
}
return out;
};
vector<int> :: iterator it1, it2;
vector<bool> h(n + 1);
vector<pii> qs[k + 2];
ll out = 0;
for (int i = 1; i <= n; i++){
if (a[i] == b[i]){
out += a[i];
continue;
}
if (a[i] < b[i]){
it1 = lower_bound(f.begin() + 1, f.end(), a[i]);
it2 = lower_bound(f.begin() + 1, f.end(), b[i]);
int l = (int) (it1 - f.begin()), r = (int) (it2 - f.begin()) - 1, s = get(l, r);
if (s) h[i] = 1;
qs[s + 1].pb({i, b[i]});
}
else {
it1 = lower_bound(f.begin() + 1, f.end(), b[i]);
it2 = lower_bound(f.begin() + 1, f.end(), a[i]);
int l = (int) (it1 - f.begin()), r = (int) (it2 - f.begin()) - 1, s = get(l, r);
qs[s + 1].pb({i, a[i]});
}
}
ST T; T.init();
for (int i = k + 1; i > 0; i--){
if (i <= k) T.add(t[i]);
for (auto [ii, x]: qs[i]){
int k = T.get(x);
bool r = (k ^ h[ii]) % 2;
out += (r) ? b[ii] : a[ii];
}
}
cout<<out<<"\n";
}
