#include <bits/stdc++.h>
using namespace std;
#define int long long
class mst {
int n;
vector <vector <int>> tree;
void build(int num, int l, int r, vector <int> &val) {
if (l == r - 1) {
tree[num].push_back(val[l]);
return;
}
int med = (l + r) / 2;
build(2 * num + 1, l, med, val);
build(2 * num + 2, med, r, val);
merge(tree[2 * num + 1].begin(), tree[2 * num + 1].end(),
tree[2 * num + 2].begin(), tree[2 * num + 2].end(),
back_inserter(tree[num]));
}
int get(int num, int l, int r, int low, int high, int v) {
if (l >= low && r <= high) {
return r - l - (int)(lower_bound(tree[num].begin(), tree[num].end(), v) - tree[num].begin());
}
int med = (l + r) / 2;
int ans = 0;
if (med > low) {
ans += get(2 * num + 1, l, med, low, high, v);
}
if (med < high) {
ans += get(2 * num + 2, med, r, low, high, v);
}
return ans;
}
int get_ind(int num, int l, int r, int low, int high) {
if (l == r - 1) {
if (tree[num].front() >= low && tree[num].front() < high) {
return l;
}
return l - 1;
}
int med = (l + r) / 2;
if (lower_bound(tree[2 * num + 2].begin(), tree[2 * num + 2].end(), high) - lower_bound(
tree[2 * num + 2].begin(), tree[2 * num + 2].end(), low) > 0) {
return get_ind(2 * num + 2, med, r, low, high);
} else {
return get_ind(2 * num + 1, l, med, low, high);
}
}
public:
void init(int nn, vector <int> &val) {
n = nn;
tree.resize(4 * n);
build(0, 0, n, val);
}
int get(int l, int r, int v) {
if (l >= r) {
return 0;
}
return get(0, 0, n, l, r, v);
}
int get_ind(int mn, int mx) {
return get_ind(0, 0, n, mn, mx);
}
};
void init(vector <int> &val) {
for (auto &v : val) {
cin >> v;
}
}
void solve() {
int n;
cin >> n;
int k;
cin >> k;
vector <int> a(n), b(n), c(k);
for (int i = 0; i < n; ++i) {
cin >> a[i] >> b[i];
}
init(c);
mst now;
now.init(k, c);
int ans = 0;
for (int i = 0; i < n; ++i) {
int ind = now.get_ind(min(a[i], b[i]), max(a[i], b[i]));
if (ind == - 1) {
int cur = now.get(0, k, max(a[i], b[i]));
if (cur & 1) {
ans += b[i];
} else {
ans += a[i];
}
} else {
if (a[i] < b[i]) {
swap(a[i], b[i]);
}
int cur = now.get(ind, k, a[i]);
if (cur & 1) {
ans += b[i];
} else {
ans += a[i];
}
}
}
cout << ans << '\n';
}
signed main() {
cin.tie(0);
ios::sync_with_stdio(false);
solve();
}
