#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
#define pii pair<ll,ll>
#define vii vector<pair<ll,ll>>
#define vi vector<ll>
#define pll pair<ll, ll>
#define all(x) (x).begin(),(x).end()
#define siz(x) (ll)(x).size()
#define count_bits(x) __builtin_popcountll((x))
const ll M = 1e9+7;
const ll INF = 1e9;
//mt19937 mt;void random_start(){mt.seed(chrono::time_poll_cast<chrono::milliseconds>(chrono::high_resolution_clock::now()).time_since_epoch().count());}
//ll los(ll a, ll b) {return a + (mt() % (b-a+1));}
typedef tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
const ll base = 1 << 18;
ll mx[base << 1];
ll suma[base << 1];
void wgore(ll w){
mx[w] = max(mx[2*w], mx[2*w+1]);
suma[w] = suma[2*w]+suma[2*w+1];
return;
}
void akt(ll w){
w += base - 1;
mx[w] = -1;
suma[w] = 1;
w /= 2;
while(w != 0){
wgore(w);
w /= 2;
}
return;
}
ll ans = 0;
const ll MAXN = 2e5 + 5;
pii X[MAXN];
struct d{
ll vl;
ll ind;
ll typ;
};
vector<d> sweep;
bool comp(const d &d1, const d &d2){
if(d1.vl != d2.vl){
return d1.vl > d2.vl;
}
if(d1.typ != d2.typ){
return d1.typ > d2.typ;
}
return false;
}
ll oblsume(ll w, ll a, ll b, ll akt_a, ll akt_b){
if(a > b) return 0;
if(a <= akt_a and akt_b <= b){
return suma[w];
}
if(akt_a > b or akt_b < a) return 0;
ll mid = (akt_a + akt_b) / 2;
return oblsume(2 * w, a, b, akt_a, mid) + oblsume(2 * w + 1, a, b, mid + 1, akt_b);
}
ll znajdz(ll w, ll lb, ll ub, ll akt_a, ll akt_b){
if(akt_a == akt_b){
if(mx[w] >= lb and mx[w] < ub) return akt_a;
else return 0;
}
ll mid = (akt_a + akt_b) / 2;
ll vl = mx[2*w+1];
if(vl >= lb and vl < ub){
return znajdz(2 * w + 1, lb, ub, mid + 1, akt_b);
}
else{
return znajdz(2 * w, lb, ub, akt_a, mid);
}
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
ll n, k;
cin >> n >> k;
ll a, b;
for(ll i = 1; i <= n; ++i){
cin >> a >> b;
X[i] = {a, b};
sweep.push_back({max(a, b), i, 0});
}
for(ll i = 1; i <= k; ++i){
cin >> a;
mx[i + base - 1] = a;
sweep.push_back({a, i, 1});
}
for(ll i = base - 1; i > 0; --i){
wgore(i);
}
sort(all(sweep), comp);
for(auto u : sweep){
if(u.typ == 1){
akt(u.ind);
}
else{
ll C = znajdz(1, min(X[u.ind].first, X[u.ind].second), max(X[u.ind].first, X[u.ind].second), 1, base);
if(C == 0){
ll P = oblsume(1, 1, k, 1, base);
if(P % 2 == 0){
ans += X[u.ind].first;
}
else{
ans += X[u.ind].second;
}
}
else{
ll P = oblsume(1, C+1, k, 1, base);
if(P % 2 == 0){
ans += max(X[u.ind].first, X[u.ind].second);
}
else{
ans += min(X[u.ind].first, X[u.ind].second);
}
}
}
}
cout << ans << "\n";
return 0;
}
