//#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("O2")
//#pragma GCC optimize("fast-math")
#include<iostream>
#include<vector>
#include<cmath>
#include<queue>
#include<utility>
#include<algorithm>
#include<bitset>
#include<map>
#include<iomanip>
#include<set>
#include<string.h>
#include<stack>
#include <list>
#include <numeric>
#include <random>
#include<unordered_map>
#define all(x) x.begin(), x.end()
#define ln (e-s+1)
#define lc (id*2)
#define rc (id*2 + 1)
#define md ((e+s)/2)
#define dm ((e+s)/2+1)
#define pb push_back
#define ll long long
#define endl '\n'
#define mk make_pair
#define F first
#define pll pair<ll, ll>
#define S second
#define pvv pair<vector<int> , vector<int> >
#define pii pair<int,int>
#define plll pair<ll, pair<int, int> >
#define ld long double
#define mat vector<vector<ll>>
//#define int long long
using namespace std;
const int N = (int)2e5 + 5, mod = (int) 1e9 + 7;
int n, k, a[N], b[N], t[N], mn, mx;
vector<int> seg[N << 2];
void build(int id = 1,int s = 1,int e = k){
if(ln == 1){
seg[id].pb(t[s]);
return;
}build(lc, s, md), build(rc, dm, e);
for(int x : seg[lc]) seg[id].pb(x);
for(int x : seg[rc]) seg[id].pb(x);
sort(seg[id].begin(), seg[id].end());
}
pii get(int l2,int r2,int id = 1,int s = 1,int e = k){
if(l2 > e || r2 < s) return {mod, 0};
if( l2 <= s && e <= r2){
int l = 0, r = seg[id].size() - 1, ans = -1;
while(l <= r){
int mid = (l+r) >> 1;
if(seg[id][mid] >= mn) ans = mid, r = mid - 1;
else l = mid + 1;
}
l = 0, r = seg[id].size() - 1;int ans2 = seg[id].size();
while(l <= r){
int mid = (l+r) >> 1;
if(seg[id][mid] >= mx) ans2 = mid, r = mid - 1;
else l = mid + 1;
}
if(ans == -1) return {mod , 0};
return {seg[id][ans], seg[id].size() - ans2};
}
auto g1 = get(l2, r2, lc, s, md), g2 = get(l2, r2, rc, dm, e);
return {min(g1.F, g2.F), g1.S + g2.S} ;
}
int main(){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> k;
for(int i = 1; i <= n; i ++) cin >> a[i] >> b[i];
for(int i = 1; i <= k; i ++) cin >> t[i];
build();
ll ret = 0;
for(int i = 1; i <= n; i ++){
int l = 1, r = k, ans = k+1;
mn = min(a[i], b[i]), mx = max(a[i], b[i]);
while(l <= r){
int mid = (l+r) >> 1;
if(get(mid, k).F >= mx) ans = mid, r = mid - 1;
else l = mid + 1;
}
// cout << "few : " << ans << endl;
if(get(1, ans - 1).F < mx){
if(get(ans, k).S %2 == 0) ret += mx;
else ret += mn;
}
else{
if(get(ans , k).S % 2 == 0) ret += a[i];
else ret += b[i];
}
// cout << ret << endl;
}cout << ret << endl;
}
