#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#define indexed_set tree<int, null_type, less_equal<int>, rb_tree_tag,tree_order_statistics_node_update>
using namespace __gnu_pbds;
using namespace std;
const int N = 3 * 2 * 1000 * 100 + 10, LG = 20;
int n, k, a[N], b[N], t[N], kol[N];
indexed_set fen[N];
void UPD(int id, int x) {
kol[id]++;
fen[id].insert(x);
}
void upd(int x, int y) {
for (++x; x < N; x += x & -x)
UPD(x, y);
}
int GET(int id, int x) {
return fen[id].order_of_key(x);
}
int get(int x, int y) {
int res = 0;
for (; x; x -= x & -x)
res += kol[x] - GET(x, y);
return res;
}
inline int inp() {
int res = 0;
char c = '0';
while (c >= '0' && c <= '9') {
((res *= 10) += c - '0');
c = getchar();
}
return res;
}
int main() {
ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
n = inp(), k = inp();
vector<int> all;
for (int i = 0; i < n; i++) {
a[i] = inp(), b[i] = inp();
for (auto x: {a[i], b[i]})
all.push_back(x);
}
for (int i = 0; i < k; i++)
t[i] = inp(), all.push_back(t[i]);
sort(all.begin(), all.end());
all.resize(unique(all.begin(), all.end()) - all.begin());
for (int i = 0; i < n; i++)
for (auto x: {&a[i], &b[i]})
*x = lower_bound(all.begin(), all.end(), *x) - all.begin();
for (int i = 0; i < k; i++)
t[i] = lower_bound(all.begin(), all.end(), t[i]) - all.begin();
reverse(t, t + k);
for (int i = 0; i < k; i++)
upd(i, t[i]);
long long ans = 0;
for (int i = 0; i < n; i++) {
int fl = 0;
if (a[i] > b[i])
fl++, swap(a[i], b[i]);
int ind = 0;
for (int j = LG - 1; j >= 0; j--) {
if (ind + (1 << j) > k)
continue;
int id = ind + (1 << j);
int x = GET(id, b[i]) - GET(id, a[i]);
if (x == 0)
ind += 1 << j;
}
int res = get(ind, b[i]);
if (ind == k) {
fl += res;
ans += (fl & 1? all[b[i]]: all[a[i]]);
}
else {
fl = 0;
fl += res;
swap(a[i], b[i]);
ans += (fl & 1? all[b[i]]: all[a[i]]);
}
}
printf("%lld\n", ans);
return 0;
}
