#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const int N = 6e5 + 5, inf = 1e9;
#define pb push_back
#define mp make_pair
#define ll long long
#define ff first
#define ss second
#define all(a) a.begin(),a.end()
#define sz(x) (int)x.size()
typedef vector<int> vi;
typedef pair<int,int> ii;
typedef vector<ii> vii;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int a[N], b[N], t[N], st[4 * N], bit[N], n, k, siz;
vi q[N];
void update(int v, int l, int r, int idx, int x){
if(l > idx || r < idx)return;
if(l == idx && r == idx){
st[v] = x;
return;
}
int mid = (l + r) / 2;
update(v * 2, l, mid, idx, x);
update(v * 2 + 1, mid + 1, r, idx, x);
st[v] = max(st[v * 2], st[v * 2 + 1]);
}
int query(int v, int l, int r, int ql, int qr){
if(l > qr || r < ql)return 0;
if(l >= ql && r <= qr)return st[v];
int mid = (l + r) / 2;
return max(query(v * 2, l, mid, ql, qr), query(v * 2 + 1, mid + 1, r, ql, qr));
}
void add(int i){
if(!i)return;
while(i <= siz){
bit[i]++;
i += (i & (-i));
}
}
int sum(int i){
int res = 0;
while(i > 0){
res += bit[i];
i -= (i & (-i));
}
return res;
}
int rangesum(int l, int r){
return sum(r) - sum(l - 1);
}
int main(){
ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
cin >> n >> k;
vi v;
for(int i = 1; i <= n; i++){
cin >> a[i] >> b[i];
v.pb(a[i]);
v.pb(b[i]);
}
for(int i = 1; i <= k; i++){
cin >> t[i];
v.pb(t[i]);
}
sort(all(v));
v.resize(distance(v.begin(), unique(all(v))));
siz = v.size();
for(int i = 1; i <= k; i++){
t[i] = lower_bound(all(v), t[i]) - v.begin() + 1;
update(1, 1, siz, t[i], i);
}
ll ans = 0;
for(int i = 1; i <= n; i++){
if(a[i] == b[i]){
ans += a[i];
continue;
}
a[i] = lower_bound(all(v), a[i]) - v.begin() + 1;
b[i] = lower_bound(all(v), b[i]) - v.begin() + 1;
int mx = query(1, 1, siz, min(a[i], b[i]), max(a[i], b[i]) - 1);
if(mx && a[i] < b[i])swap(a[i], b[i]);
q[mx].pb(i);
}
for(int i = k; i >= 0; i--){
for(auto x : q[i]){
int cnt = rangesum(max(a[x], b[x]), siz);
if(cnt & 1){
swap(a[x], b[x]);
}
ans += v[a[x] - 1];
}
add(t[i]);
}
cout << ans << '\n';
return 0;
}
