// IN THE NAME OF ALLAH
#include<bits/stdc++.h>
using namespace std;
#define fast ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define wall cerr << "------------------------------------" << endl
#define pb push_back
#define F first
#define S second
#define all(x) x.begin() , x.end()
#define int ll
#define kids int tm = (tl + tr)>>1; int cl = v<<1; int cr = v<<1|1
#define test int n; cin >> n; while(n--)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#pragma GCC optimize("Ofast")
typedef long long ll;
typedef pair<int , int> pii;
typedef pair<ll , ll> pll;
const int N = 6e5 + 10;
const int K = 800+10;
const ll mod = 998244353;
const ll INF = 1e18+10;
const int P = 31;
const int lg = 25;
int t[N] , q;
int a[N] , b[N] , n;
int A[N] , B[N];
int rmq[3*N][lg];
int ty[N] , tim[N];
vector<int> qu[N];
int seg[N << 2];
int la[N << 2];
void init() {
for(int i = 1 ; i < lg ; i++)
for(int j = 1 ; j <= q ; j++) {
if(q-j+1 < (1ll << i))
continue;
rmq[j][i] = max(rmq[j][i-1] , rmq[j + (1ll << (i-1))][i-1]);
}
}
int ask_rmq(int l , int r) {
int x = log2(r-l+1);
return max(rmq[l][x] , rmq[r - (1ll << x) + 1][x]);
}
void shift(int v , int tl , int tr) {
if(la[v] == 0)
return;
seg[v] ^= 1;
if(tl != tr)
la[v << 1] ^= 1 , la[v << 1 | 1] ^= 1;
la[v] = 0;
}
void upd(int v , int tl , int tr , int l , int r) {
shift(v , tl , tr);
if(l > r)
return;
if(tl == l && tr == r) {
la[v] ^= 1;
shift(v , tl , tr);
return;
}
kids;
upd(cl , tl , tm , l , min(tm , r));
upd(cr , tm+1 , tr , max(tm+1 , l) , r);
}
void fix(int v , int tl , int tr , int pos , int x) {
shift(v , tl , tr);
if(tl == tr) {
seg[v] = x;
return;
}
kids;
if(tm >= pos)
fix(cl , tl , tm , pos , x);
else
fix(cl , tm+1 , tr , pos , x);
}
int ask(int v , int tl , int tr , int pos) {
shift(v , tl , tr);
if(tl == tr)
return seg[v];
kids;
if(tm >= pos)
return ask(cl , tl , tm , pos);
return ask(cr , tm+1 , tr , pos);
}
void solve() {
cin >> n >> q;
vector<pair<int , pii>> vec;
for(int i = 1 ; i <= n ; i++) {
cin >> a[i] >> b[i];
vec.pb({max(a[i] , b[i]) , {a[i] , b[i]}});
}
vec.pb({-INF , {-INF , -INF}});
sort(all(vec));
for(int i = 1 ; i <= n ; i++)
a[i] = vec[i].S.F , b[i] = vec[i].S.S;
// wall;
// cout << "check0 :\n";
// for(int i = 1 ; i <= n ; i++)
// cout << a[i] << " " << b[i] << "\n";
// wall;
vector<pii> ve;
for(int i = 1 ; i <= q ; i++) {
cin >> t[i];
ve.pb({t[i] , i});
}
ve.pb({-INF , -INF});
sort(all(ve));
for(int i = 1 ; i <= q ; i++)
rmq[i][0] = ve[i].S;
init();
for(int i = 1 ; i <= n ; i++) {
if(a[i] == b[i])
continue;
int x = a[i] , y = b[i];
if(x > y)
swap(x , y);
ty[i] = 0;
if(a[i] < b[i]) ty[i] = 1;
int l = -1 , r = q+1;
if(ve[q].F >= x)
l = lower_bound(all(ve) , make_pair(x , -INF)) - ve.begin();
if(ve[q].F >= y)
r = lower_bound(all(ve) , make_pair(y , -INF)) - ve.begin();
r--;
if(l == -1 || r == 0 || l > r)
continue;
tim[i] = ask_rmq(l , r);
qu[tim[i]].pb(i);
}
// wall;
// cout << "check1 :\n";
// for(int i = 1 ; i <= n ; i++) {
// cout << i << " " << ty[i] << " " << tim[i] << "\n";
// }
// wall;
// cout << "check2 :\n";
// for(int i = 1 ; i <= q ; i++) {
// cout << i << " :\n";
// for(auto u : qu[i])
// cout << u << " " << ty[u] << "\n";
// }
// wall;
for(int i = 1 ; i <= q ; i++) {
auto it = lower_bound(all(vec) , make_pair(t[i]+1 , make_pair(-INF , -INF)));
int ind = n;
if(it != vec.end())
ind = it - vec.begin() - 1;
upd(1 , 1 , n , 1 , ind);
// cout << "id = " << ind << " : ";
for(auto u : qu[i]) {
int x = ask(1 , 1 , n , u);
// cout << x << " - ";
if(x != ty[u])
upd(1 , 1 , n , u , u);
}
// cout << "\n";
}
int ans = 0;
for(int i = 1 ; i <= n ; i++)
ans += (ask(1 , 1 , n , i) == 1 ? b[i] : a[i]);
cout << ans << "\n";
}
signed main()
{
solve();
}
// IT'S EASY TO SEE
// CODE = LOVE
