#include <bits/stdc++.h>
#define int long long
#define debug cout << "ok\n";
#define SQR(x) (1LL * ((x) * (x)))
#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define pii pair<int,int>
#define pli pair<ll,int>
#define vi vector<int>
#define FAST ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef unsigned int ui;
using namespace std;
const int M = 1e9 + 7;
const int INF = 1e9 + 7;
const ll INFLL = (ll)2e18 + 7LL;
const ld PI = acos(-1);
const int dx[] = {1, -1, 0, 0, -1, 1, 1, -1};
const int dy[] = {0, 0, 1, -1, -1, -1, 1, 1};
template<class _, class __>
bool minimize(_ &x, const __ y){
if(x > y){
x = y;
return true;
} else return false;
}
template<class _, class __>
bool maximize(_ &x, const __ y){
if(x < y){
x = y;
return true;
} else return false;
}
template<class _,class __>
void Add(_ &x, const __ y) {
x += y;
if (x >= M) {
x -= M;
}
return;
}
template<class _,class __>
void Diff(_ &x, const __ y) {
x -= y;
if (x < 0) {
x += M;
}
return;
}
//--------------------------------------------------------------
const int MaxN = 1e6+7;
int n,K,a[MaxN],b[MaxN],f[MaxN],t[MaxN],lst[MaxN];
vi lis[MaxN];
vi nen;
struct FenwickTree {
vi FW;
int n;
void Set(int _n) {
n = _n;
FW.assign(n+1,0);
}
int Get(int u) {
int res = 0;
for (;u;u-=u&-u) {
res += FW[u];
}
return res;
}
int Get(int l,int r) {
return Get(r) - Get(l-1);
}
void Upd(int u,int v) {
for (;u<=n;u+=u&-u) {
FW[u] += v;
}
}
} Fw;
struct SegmentTree {
vi Tr;
int n;
void Set(int _n) {
n = _n;
Tr.assign(n*4+7,0);
}
void UT(int id,int l,int r,int u,int v) {
if (l > u || r < u) return;
if (l == r) {
maximize(Tr[id],v);
return;
}
int m = (l+r) >> 1;
UT(id<<1,l,m,u,v);
UT(id<<1|1,m+1,r,u,v);
Tr[id] = max(Tr[id<<1],Tr[id<<1|1]);
}
int GV(int id,int l,int r,int ls,int rs) {
if (l > rs || r < ls) return 0;
if (ls <= l && r <= rs) return Tr[id];
int m = (l+r) >> 1;
return max(GV(id<<1,l,m,ls,rs),GV(id<<1|1,m+1,r,ls,rs));
}
int Get(int l,int r) {
return GV(1,1,n,l,r);
}
void Upd(int u,int v) {
UT(1,1,n,u,v);
}
} Seg;
void sol() {
cin >> n >> K;
for (int i=1;i<=n;i++) {
cin >> a[i] >> b[i];
if (a[i] > b[i]) {
swap(a[i],b[i]);
f[i] = 1;
}
nen.pb(a[i]);
nen.pb(b[i]);
}
for (int i=1;i<=K;i++) {
cin >> t[i];
nen.pb(t[i]);
}
sort(nen.begin(),nen.end());
nen.erase(unique(nen.begin(),nen.end()),nen.end());
for (int i=1;i<=n;i++) {
a[i] = lower_bound(nen.begin(),nen.end(),a[i]) - nen.begin() + 1;
b[i] = lower_bound(nen.begin(),nen.end(),b[i]) - nen.begin() + 1;
}
for (int i=1;i<=K;i++) {
t[i] = lower_bound(nen.begin(),nen.end(),t[i]) - nen.begin() + 1;
}
Seg.Set(nen.size());
for (int i=1;i<=K;i++) {
Seg.Upd(t[i],i);
}
for (int i=1;i<=n;i++) {
lst[i] = Seg.Get(a[i],b[i]-1);
lis[lst[i]].pb(i);
if (lst[i]) f[i] = 1;
}
Fw.Set(nen.size());
t[0] = 1;
for (int i=K;i>=0;i--) {
for (int u : lis[i]) {
f[u] += Fw.Get(b[u],nen.size());
}
Fw.Upd(t[i],1);
}
int res = 0;
for (int i=1;i<=n;i++) {
if (f[i] & 1) res += nen[b[i]-1];
else res += nen[a[i]-1];
}
cout << res;
}
signed main() {
// freopen("test.inp","r",stdin);
// freopen("test.out","w",stdout);
FAST
int t=1;
// cin >> t;
while (t--) sol();
}
