#include<bits/stdc++.h>
#define endl '\n'
#define fi first
#define se second
#define pb push_back
#define bit(s, i) (s & (1<<i))
using namespace std;
const int N = 2e5 + 5;
const int M = 1;
const int K = 1;
const int mod = 1e9+7;
const int inf = 2e9;
const long long Inf = 2e18;
typedef long long ll;
typedef pair < int, int > ii;
int n, k, a[N], b[N], c[N], poss[N], final[N];
vector < int > val;
vector < ii > reqry;
/// IT
int IT[4 * N];
void update(int id, int l, int r, int pos, int x) {
if(l > pos || r < pos) return;
if(l == r) {
IT[id] = max(IT[id], x);
return;
}
int mid = (l + r) >> 1;
update(id<<1, l, mid, pos, x);
update(id<<1|1, mid + 1, r, pos, x);
IT[id] = max(IT[id<<1], IT[id<<1|1]);
}
int query(int id, int l, int r, int u, int v) {
if(l > v || r < u) return 0;
if(u <= l && r <= v) return IT[id];
int mid = (l + r) >> 1;
return max(query(id<<1, l, mid, u, v), query(id<<1|1, mid + 1, r, u, v));
}
/// BIT
int BIT[N];
void up(int id) {
id = lower_bound(val.begin(), val.end(), id) - val.begin() + 1;
for(; id; id -= id&-id) BIT[id] ++;
}
int get(int id) {
id = lower_bound(val.begin(), val.end(), id) - val.begin() + 1;
int tmp = 0;
for(; id <= k; id += id&-id) tmp += BIT[id];
return tmp;
}
int main()
{
ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
if(fopen("trash.inp", "r")) {
freopen("trash.inp","r",stdin);
freopen("trash.out","w",stdout);
}
cin >> n >> k;
for(int i=1;i<=n;++i) cin >> a[i] >> b[i];
for(int i=1;i<=k;++i) {
cin >> c[i];
val.pb(c[i]);
}
sort(val.begin(), val.end());
for(int i=1;i<=k;++i) {
int cur = lower_bound(val.begin(), val.end(), c[i]) - val.begin() + 1;
update(1, 1, k, cur, i);
}
for(int i=1;i<=n;++i) {
int mi = min(a[i], b[i]);
int ma = max(a[i], b[i]);
int L = lower_bound(val.begin(), val.end(), mi) - val.begin() + 1;
int R = lower_bound(val.begin(), val.end(), ma) - val.begin();
int cur = query(1, 1, k, L, R);
poss[i] = cur;
reqry.pb({cur, i});
}
sort(reqry.begin(), reqry.end());
int run = 1;
for(ii i : reqry) {
while(run <= i.fi) up(c[run ++ ]);
int ma = max(a[i.se], b[i.se]);
int ans = get(ma);
int res = k - (lower_bound(val.begin(), val.end(), ma) - val.begin());
final[i.se] = res - ans;
// cout << i.se << ' ' << res << ' ' << ans << endl;
}
ll kqua = 0;
for(int i=1;i<=n;++i) {
if(!poss[i]) {
if(final[i]&1) kqua += b[i];
else kqua += a[i];
}
else {
int cur = (a[i] < b[i]) ^ (final[i]&1);
if(cur) kqua += b[i];
else kqua += a[i];
}
}
cout << kqua;
}
