#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll S = (1 << 21);
struct MaxSegTree{
ll T[2 * S] = {};
void update(ll k, ll v) { update(1, 1, S, k, v); }
ll query(ll l, ll r) { return query(1, 1, S, l, r); }
void update(ll node, ll s, ll e, ll k, ll v){
if (s == e){
T[node] = max(T[node], v);
return;
}
ll m = (s + e) / 2;
ll lch = 2 * node, rch = 2 * node + 1;
if (k <= m) update(lch, s, m, k, v);
else update(rch, m + 1, e, k, v);
ll x = T[lch], y = T[rch];
T[node] = max(x, y);
}
ll query(ll node, ll s, ll e, ll l, ll r){
if (e < l || s > r) return 0;
if (l <= s && e <= r) return T[node];
ll m = (s + e) / 2;
ll lch = 2 * node, rch = 2 * node + 1;
ll x = query(lch, s, m, l, r), y = query(rch, m + 1, e, l, r);
return max(x, y);
}
};
struct MergeSortTree{
vector<ll> T[2 * S];
ll query(ll l, ll r, ll k) {return query(1, 1, S / 2, l, r, k);}
void init(){
for(int i = S / 2 - 1; i >= 1; i--){
vector<ll> &L = T[i * 2], &R = T[i * 2 + 1];
T[i].resize(L.size() + R.size());
merge(L.begin(), L.end(), R.begin(), R.end(), T[i].begin());
}
}
void push(ll k, ll v){
T[k + S / 2 - 1].push_back(v);
}
ll query(ll node, ll s, ll e, ll l, ll r, ll v){
if(e < l || s > r) return 0;
if(l <= s && e <= r) return T[node].end() - lower_bound(T[node].begin(), T[node].end(), v);
ll m = (s + e) / 2, lch = node * 2, rch = node * 2 + 1;
ll x = query(lch, s, m, l, r, v);
ll y = query(rch, m + 1, e, l, r, v);
return x + y;
}
};
vector<ll> V;
map<ll, ll> mp;
MaxSegTree MT;
MergeSortTree SRT;
ll Index(ll n){
return lower_bound(V.begin(), V.end(), n) - V.begin() + 1;
}
ll N, K;
ll A[400005];
ll B[400005];
ll Q[400005];
int main(){
cin.tie(0) -> sync_with_stdio(false);
cin >> N >> K;
for(int i = 1; i <= N; i++){
cin >> A[i] >> B[i];
V.push_back(A[i]); V.push_back(B[i]);
}
for(int i = 1; i <= K; i++){
cin >> Q[i];
V.push_back(Q[i]);
}
sort(V.begin(), V.end());
V.erase(unique(V.begin(), V.end()), V.end());
for(int i = 1; i <= N; i++){
mp[Index(A[i])] = A[i];
A[i] = Index(A[i]);
mp[Index(B[i])] = B[i];
B[i] = Index(B[i]);
}
for(int i = 1; i <= K; i++){
mp[Index(Q[i])] = Q[i];
Q[i] = Index(Q[i]);
MT.update(Q[i], i);
SRT.push(i, Q[i]);
}
SRT.init();
ll ans = 0;
for(int i = 1; i <= N; i++){
ll C = min(A[i], B[i]), D = max(A[i], B[i]);
ll Last = MT.query(C, D - 1);
ll R = SRT.query(Last + 1, K, D);
if(Last == 0) C = B[i], D = A[i];
if(R % 2 == 0){
ans += mp[D];
} else {
ans += mp[C];
}
}
cout << ans;
}
