#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair < int , int > pii;
const int maxn = 2e5 + 10;
const int mod = 1e9 + 7;
#define endl '\n'
#define ms(x , y) memset(x , y , sizeof x)
#define dokme(x) cout << x , exit(0);
#define lc (v << 1)
#define rc (lc | 1)
#define mid ((l + r) >> 1)
#define ff first
#define ss second
int n , k , t[maxn] , cnt[maxn << 2];
pii a[maxn] , mx[maxn << 2];
void build(int v = 1 , int l = 1 , int r = k + 1){
if(r - l == 1){
cnt[v] = 0, mx[v] = {t[l] , l};
return;
}
build(lc , l , mid);
build(rc , mid , r);
cnt[v] = cnt[lc] + cnt[rc];
mx[v] = max(mx[lc] , mx[rc]);
}
void shift(int pos , int v = 1 , int l = 1 , int r = k + 1){
if(r - l == 1){
cnt[v] = 1 , mx[v] = {-1 , l};
return;
}
if(pos < mid)
shift(pos , lc , l , mid);
else
shift(pos , rc , mid , r);
cnt[v] = cnt[lc] + cnt[rc];
mx[v] = max(mx[lc] , mx[rc]);
}
int get(int L , int R , int v = 1 , int l = 1 , int r = k + 1){
if(r <= L or R <= l)return 0;
if(L <= l and r <= R)return cnt[v];
return get(L , R , lc , l , mid) + get(L , R , rc , mid , r);
}
int dfs(int x , int v = 1 , int l = 1 , int r = k + 1){
if(r - l == 1)
return l;
if(mx[rc].ff >= x)return dfs(x , rc , mid, r);
return dfs(x , lc , l , mid);
}
int32_t main(){
ios::sync_with_stdio(0), cin.tie(0);
cin >> n >> k;
for(int i = 1 ; i <= n ; i ++)
cin >> a[i].ff >> a[i].ss;
sort(a + 1 , a + 1 + n , [](pii a , pii b){return max(a.ff , a.ss) > max(b.ff , b.ss);});
for(int i = 1 ; i <= k ; i ++)
cin >> t[i];
build();
ll ans = 0;
for(int i = 1 ; i <= n ; i ++){
bool swp = a[i].ff < a[i].ss;
if(swp)swap(a[i].ff , a[i].ss);
while(mx[1].ff >= a[i].ff)
shift(mx[1].ss);
if(mx[1].ff >= a[i].ss)
ans += ((get(dfs(a[i].ss) , k + 1) % 2) ? a[i].ss : a[i].ff);
else
ans += ((swp) ? ((cnt[1]%2) ? a[i].ff : a[i].ss) : (((cnt[1]%2) ? a[i].ss : a[i].ff)));
}
cout << ans;
return 0;
}
