#include <bits/stdc++.h>
#define F first
#define S second
#define PB push_back
#define PF push_front
#define MP make_pair
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
const int maxn = 2e5 + 4;
const int maxl = 23;
int seg[maxl][4 * maxn], t[maxn], a[maxn], b[maxn];
int get2 (int id, int L, int R, int l, int r, int lb, int h = 0) {
if (L == l and R == r) {
int fi = lower_bound (seg[h] + L, seg[h] + R, lb) - seg[h];
return R - fi;
}
int mid = (L + R) >> 1, ret = 0;
if (mid > l)
ret += get2 (2 * id + 0, L, mid, l, min (mid, r), lb, h + 1);
if (mid < r)
ret += get2 (2 * id + 1, mid, R, max (l, mid), r, lb, h + 1);
return ret;
}
int get (int id, int L, int R, int lb, int ub, int h = 0) {
int idx = lower_bound (seg[h] + L, seg[h] + R, lb) - seg[h];
if (idx == R or seg[h][idx] >= ub)
return -1;
if (L + 1 == R)
return L;
int mid = (L + R) >> 1;
int ret = get (2 * id + 1, mid, R, lb, ub, h + 1);
if (ret != -1)
return ret;
return get (2 * id + 0, L, mid, lb, ub, h + 1);
}
void build (int id, int L, int R, int h = 0) {
if (L + 1 == R) {
seg[h][L] = t[L];
return;
}
int mid = (L + R) >> 1;
build (2 * id + 0, L, mid, h + 1);
build (2 * id + 1, mid, R, h + 1);
for (int i = L; i < R; i++)
seg[h][i] = seg[h + 1][i];
sort (seg[h] + L, seg[h] + R);
}
int main () {
ios::sync_with_stdio(false);
int n, k;
cin >> n >> k;
for (int i = 0; i < n; i++)
cin >> a[i] >> b[i];
for (int i = 0; i < k; i++)
cin >> t[i];
build (1, 0, k);
ll ans = 0;
for (int i = 0; i < n; i++) {
int fi = a[i], se = b[i];
if (fi == se) {
ans += fi;
continue;
}
if (fi > se)
swap (fi, se);
int idx = get (1, 0, k, fi, se);
if (idx == -1) {
int x = get2 (1, 0, k, 0, k, se);
if (x % 2 == 0)
ans += a[i];
else
ans += b[i];
}
else {
int x = get2 (1, 0, k, idx, k, se);
if (x % 2 == 0)
ans += se;
else
ans += fi;
}
}
cout << ans << endl;
}
