#include <bits/stdc++.h>
using namespace std;
template<typename T>
void out(T x) { cout << x << endl; exit(0); }
#define watch(x) cout << (#x) << " is " << (x) << endl
using ll = long long;
const ll mod = 1e9+7;
const int maxn = 2e5+10;
const int inf = 2e9;
int n, k;
vector<array<int,2>> card;
vector<pair<int,int>> flip; // value, index
bool sum[maxn*4];
int tmin[maxn*4];
void build(int v, int tl, int tr) {
if (tl==tr) {
tmin[v]=inf;
} else {
int tm=(tl+tr)/2;
build(2*v,tl,tm);
build(2*v+1,tm+1,tr);
tmin[v]=min(tmin[2*v],tmin[2*v+1]);
}
}
void upd(int v, int tl, int tr, int i, int val) {
if (tl==tr) {
tmin[v] = val;
sum[v] = true;
} else {
int tm=(tl+tr)/2;
if (i<=tm) {
upd(2*v,tl,tm,i,val);
} else {
upd(2*v+1,tm+1,tr,i,val);
}
tmin[v] = min(tmin[2*v], tmin[2*v+1]);
sum[v] = sum[2*v] ^ sum[2*v+1];
}
}
// 0: everything is >= val
// get first index from rhs that is < val
int get(int v, int tl, int tr, int val) {
if (val <= tmin[v]) {
return 0;
}
if (tl==tr) {
assert(tmin[v]<val);
return tl;
} else {
int tm=(tl+tr)/2;
int rhs = get(2*v+1,tm+1,tr,val);
if (rhs > 0) {
return rhs;
}
return get(2*v,tl,tm,val);
}
}
bool qry(int v, int tl, int tr, int l, int r) {
if (l>r) return false;
if (l==tl && tr==r) return sum[v];
int tm=(tl+tr)/2;
return qry(2*v,tl,tm,l,min(r,tm)) ^ qry(2*v+1,tm+1,tr,max(tm+1,l),r);
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin>>n>>k;
card.resize(n);
for (int i=0; i<n; i++) {
cin>>card[i][0]>>card[i][1];
}
flip.resize(k);
for (int i=1; i<=k; i++) {
cin>>flip[i-1].first;
flip[i-1].second=i;
}
sort(flip.rbegin(),flip.rend());
sort(card.begin(), card.end(), [&](array<int,2> c1, array<int,2> c2) {
return min(c1[0],c1[1]) > min(c2[0],c2[1]);
});
build(1,1,k);
ll res = 0;
int j=0;
for (auto ca: card) {
int lo = min(ca[0], ca[1]);
int hi = max(ca[0], ca[1]);
bool flag = false;
if (lo == ca[0]) {
flag = true;
swap(ca[0], ca[1]);
}
assert(ca[0] >= ca[1]);
while (j<k && flip[j].first >= lo) {
upd(1,1,k,flip[j].second,flip[j].first);
j++;
}
int p = get(1,1,k,hi);
// p=0 if every card >= hi
bool parity = (p==k ? false : qry(1,1,k,p+1,k));
if (flag && p==0) {
parity=!parity;
}
//cout<<ca[0]<<" "<<ca[1]<<": "<<ca[parity]<<endl;
res += ca[parity];
}
cout<<res<<endl;
return 0;
}
