#include <bits/stdc++.h>
using namespace std;
#define int long long
int n, k, ans;
vector<pair<pair<int, int>, int>> crs;
vector<pair<int, int>> qs;
const int MXN = 40005;
int seg[MXN * 4];
void build(int ind, int l, int r) {
if (l == r) {
seg[ind] = qs[l].second;
return;
}
int m = (l + r) / 2;
build(ind*2, l, m);
build(ind*2+1, m+1, r);
seg[ind] = max(seg[ind*2], seg[ind*2+1]);
}
int query(int ind, int l, int r, int ql, int qr) {
if (ql <= l && r <= qr) return seg[ind];
if (ql > r || qr < l) return -1;
int m = (l + r) / 2;
return max(query(ind*2, l, m, ql, qr), query(ind*2+1, m+1, r, ql, qr));
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
cin >> n >> k;
for (int i=0; i<n; i++) {
int a, b;
cin >> a >> b;
if (a == b) {
ans += a;
continue;
}
int s = 0;
if (a > b) {
swap(a, b); s = 1;
}
crs.push_back({{a, b}, s});
}
n = crs.size();
for (int i=0; i<k; i++) {
int x;
cin >> x;
qs.push_back({x, i});
}
sort(qs.begin(), qs.end());
build(1, 0, k-1);
for (auto x: crs) {
int a = x.first.first, b = x.first.second;
int e = lower_bound(qs.begin(), qs.end(), make_pair(a, 0ll)) - qs.begin();
int f = upper_bound(qs.begin(), qs.end(), make_pair(b-1, k)) - qs.begin() - 1;
int ls = query(1, 0, k-1, e, f);
int up = x.second;
if (ls != -1) up = 1;
int flips = 0;
for (int j=f+1; j<qs.size(); j++) {
if (qs[j].second > ls) flips++;
}
if (flips % 2 == 1) up = 1 - up;
if (up) ans += b;
else ans += a;
}
cout << ans << endl;
}
