/*
IN THE NAME OF GOD
*/
#include <bits/stdc++.h>
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef long double ld;
#define F first
#define S second
#define Mp make_pair
#define pb push_back
#define pf push_front
#define size(x) ((ll)x.size())
#define all(x) (x).begin(),(x).end()
#define kill(x) cout << x << '\n', exit(0);
#define fuck(x) cout << "(" << #x << " , " << x << ")" << endl
#define endl '\n'
const int N = 1e6+1e5+23, lg = 20;
ll Mod = 1e9+7; //998244353;
inline ll MOD(ll a, ll mod=Mod) {a%=mod; (a<0)&&(a+=mod); return a;}
inline ll poww(ll a, ll b, ll mod=Mod) {
ll ans = 1;
a=MOD(a, mod);
while (b) {
if (b & 1) ans = MOD(ans*a, mod);
b >>= 1;
a = MOD(a*a, mod);
}
return ans;
}
int n, k, a[N], b[N], ans[N], seg[2*N], t[N], fen[N];
vector<int> comp, Q[N];
int get(int val) {
int ptr = lower_bound(all(comp), val) - comp.begin() + 1;
return ptr;
}
void upd(int ind, int val) {
if(ind == 0) return ;
if(ind >= (1<<lg)) seg[ind] = val;
else seg[ind] = max(seg[2*ind], seg[2*ind+1]);
upd(ind/2, val);
}
int query(int l, int r, int ind=1, int lc=1, int rc=(1<<lg)+1) {
if(l>=rc || lc>=r) return 0;
if(lc>=l && rc<=r) return seg[ind];
int mid = (lc+rc)/2;
return max(query(l, r, 2*ind, lc, mid), query(l, r, 2*ind+1, mid, rc));
}
void add(int ind, int val) {
while(ind < N) {
fen[ind] += val; ind += (ind&(-ind));
}
}
int qry(int ind) {
int res=0; while(ind>0) {res+=fen[ind]; ind-=(ind&(-ind));} return res;
}
int main () {
ios_base::sync_with_stdio(false), cin.tie(0);
cin>>n>>k;
for(int i=1; i<=n; i++) {
cin>>a[i]>>b[i];
comp.pb(a[i]); comp.pb(b[i]);
}
for(int i=1; i<=k; i++) {
cin>>t[i]; comp.pb(t[i]);
}
comp.pb(1e9+1);
sort(all(comp));
comp.resize(unique(all(comp)) - comp.begin());
for(int i=1; i<=k; i++) {
upd(get(t[i])+(1<<lg)-1, i);
}
for(int i=1; i<=n; i++) {
int l=get(a[i]), r=get(b[i]);
if(l>r) swap(l,r);
Q[query(l, r)].pb(i);
}
for(int i=k; i>=0; i--) {
for(auto it : Q[i]) {
int f = qry(N-1) - qry(get(max(a[it],b[it]))-1);
if(i>0 && a[it]<b[it]) f++;
if(f%2==1) ans[it] = b[it];
else ans[it] = a[it];
}
add(get(t[i]), 1);
}
ll answ = 0;
for(int i=1; i<=n; i++) answ += ((ll)ans[i]);
cout<<answ<<endl;
return 0;
}
