#include <bits/stdc++.h>
#define pb push_back
#define ll long long
#define ff first
#define ss second
using namespace std;
const int maxN = 2e5 + 5;
const int inf = 1e9;
int a[maxN], b[maxN], t[maxN], st[maxN * 4], fen[maxN], n, k, sz;
vector<int> q[maxN];
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 <= sz){
fen[i]++;
i += (i & (-i));
}
}
int sum(int i){
int res = 0;
while(i > 0){
res += fen[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;
vector<int> 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(v.begin(), v.end());
v.resize(distance(v.begin(), unique(v.begin(), v.end())));
sz = v.size();
for(int i = 1; i <= k; i++){
t[i] = lower_bound(v.begin(), v.end(), t[i]) - v.begin() + 1;
update(1, 1, v.size(), t[i], i);
}
ll res = 0;
for(int i = 1; i <= n; i++){
if(a[i] == b[i]){
res += a[i];
continue;
}
a[i] = lower_bound(v.begin(), v.end(), a[i]) - v.begin() + 1;
b[i] = lower_bound(v.begin(), v.end(), b[i]) - v.begin() + 1;
int mx = query(1, 1, v.size(), 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 = sum(sz) - sum(max(a[x], b[x]) - 1);
if(cnt & 1)
swap(a[x], b[x]);
res += v[a[x] - 1];
}
add(t[i]);
}
cout << res << endl;
return 0;
}
