#include <bits/stdc++.h>
using namespace std;
#define POPCOUNT(n) (__builtin_popcountll((n)))
#define CLZ(n) (__builtin_clzll((n)))
#define CTZ(n) (__builtin_ctzll((n)))
#define LOG(n) (63 - __builtin_clzll((n)))
#define BIT(n, i) (((n) >> (i)) & 1ll)
#define MASK(i) (1ll << (i))
#define FLIP(n, i) ((n) ^ (1ll << (i)))
#define ON(n, i) ((n) | MASK(i))
#define OFF(n, i) ((n) & ~MASK(i))
#define Int __int128
#define fi first
#define se second
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef pair<long long, int> pli;
typedef pair<int, long long> pil;
typedef vector<pair<int, int>> vii;
typedef vector<pair<long long, long long>> vll;
typedef vector<pair<long long, int>> vli;
typedef vector<pair<int, long long>> vil;
template <class T1, class T2> bool maximize(T1 &x, T2 y) {
if (x < y) {
x = y;
return true;
}
return false;
}
template <class T1, class T2> bool minimize(T1 &x, T2 y) {
if (x > y) {
x = y;
return true;
}
return false;
}
template <class T> void remove_duplicate(vector<T> &ve) {
sort (ve.begin(), ve.end());
ve.resize(unique(ve.begin(), ve.end()) - ve.begin());
}
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
long long random(long long l, long long r) {
return uniform_int_distribution<long long>(l, r)(rng);
}
unsigned long long random(unsigned long long l, unsigned long long r) {
return uniform_int_distribution<unsigned long long>(l, r)(rng);
}
template <class T> T random(T r) {
return rng() % r;
}
const int N = 1e6 + 5;
const int MOD = 1e9 + 7;
const int inf = 1e9;
const long long INF = 1e18;
int n, k;
int a[N], b[N], A[N], B[N], t[N], last[N], res[N];
struct FenwickTree {
using T = int;
vector<T> bit;
FenwickTree() {}
void resize(int n) {
bit.assign(n + 1, 0);
}
void update(int p, T val) {
// cerr << "update " << p << ' ' << val << '\n';
for (; p < int(bit.size()); p += p & -p) bit[p] += val;
}
T get(int p) {
T ans = 0;
for (; p > 0; p -= p & -p) ans += bit[p];
return ans;
}
T get_max(int p) {
T ans = 0;
for (; p > 0; p -= p & -p) maximize(ans, bit[p]);
return ans;
}
} fen;
signed main() {
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
cin >> n >> k;
for (int i = 1; i <= n; ++i) {
cin >> a[i] >> b[i];
A[i] = a[i], B[i] = b[i];
if (A[i] > B[i]) swap(A[i], B[i]);
}
for (int i = 1; i <= k; ++i) cin >> t[i];
reverse(t + 1, t + 1 + k);
vector<int> order1(n); iota(order1.begin(), order1.end(), 1);
sort (order1.begin(), order1.end(), [&](int x, int y) {
return B[x] < B[y];
});
vector<int> order2(k); iota(order2.begin(), order2.end(), 1);
sort (order2.begin(), order2.end(), [&](int x, int y) {
return t[x] < t[y];
});
// cerr << "PHTN\n";
fen.resize(k);
for (int i = 0, j = -1; i < n; ++i) {
// cerr << "i = " << i << ' ' << j << '\n';
while (j + 1 < k && t[order2[j + 1]] < B[order1[i]]) {
// cerr << order2[j + 1] << '\n';
fen.update(order2[j + 1], t[order2[j + 1]]);
++j;
}
int low = 1, high = k; last[order1[i]] = k + 1;
while (low <= high) {
int mid = (low + high) >> 1;
if (fen.get_max(mid) >= A[order1[i]]) high = (last[order1[i]] = mid) - 1;
else low = mid + 1;
}
}
// cerr << "Nguyen\n";
fen.resize(k);
for (int i = n - 1, j = k; i >= 0; --i) {
while (j > 0 && t[order2[j - 1]] >= B[order1[i]]) {
fen.update(order2[j - 1], 1);
--j;
}
int tmp = fen.get(last[order1[i]] - 1);
if (last[order1[i]] == k + 1) res[order1[i]] = (tmp & 1 ? b[order1[i]] : a[order1[i]]);
else res[order1[i]] = (tmp & 1 ? A[order1[i]] : B[order1[i]]);
}
// for (int i = 1; i <= n; ++i) cerr << res[i] << ' ';
// cerr << '\n';
// // Brute force
// for (int i = k; i > 0; --i) {
// for (int j = 1; j <= n; ++j) if (a[j] <= t[i]) {
// swap(a[j], b[j]);
// }
// }
// for (int i = 1; i <= n; ++i) cerr << a[i] << ' ';
// cerr << '\n';
ll ans = 0;
for (int i = 1; i <= n; ++i) ans += res[i];
cout << ans;
return 0;
}
