#include <bits/stdc++.h>
#define F first
#define S second
#define pii pair<int, int>
#define pb push_back
using namespace std;
typedef long long ll;
typedef long double ld;
const int N = 2e5 + 10, LOG = 20;
int n, k, a[N], b[N];
pii t[N];
int seg[LOG][N];
void build(int lg = 0, int s = 0, int e = k){
if(e - s < 2){
seg[lg][s] = t[s].S;
return ;
}
int mid = (s + e)/2;
build(lg + 1, s , mid);
build(lg + 1, mid , e);
merge(seg[lg + 1] + s, seg[lg + 1] + mid, seg[lg + 1] + mid, seg[lg + 1] + e, seg[lg] + s);
}
int get_max(int lg ,int L, int R, int s = 0, int e = k){
if(L<=s && e<=R){
return seg[lg][e - 1];
}
if(L>=e || s>=R)return -1;
int mid = (s + e)/2;
return max(get_max(lg + 1, L, R, s, mid), get_max(lg + 1, L, R, mid, e));
}
int get_cnt(int lg, int vl, int L, int R, int s = 0, int e = k){
if(L<=s && e<=R){
return (e - s) - (upper_bound(seg[lg] + s, seg[lg] + e, vl) - (seg[lg] + s));
}
if(L>=e || s>=R)return 0;
int mid = (s + e)/2;
return get_cnt(lg + 1, vl, L, R, s, mid) + get_cnt(lg + 1, vl, L, R, mid, e);
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n >> k;
for(int i=0; i<n; i++)
cin >> a[i] >> b[i];
for(int i=0; i<k; i++){
cin >> t[i].F; t[i].S = i;
}
sort(t, t + k);
build();
ll sum = 0;
for(int i=0; i<n; i++){
bool turn;
if(a[i] < b[i])turn = true;
else turn = false;
int lo = lower_bound(t, t + k, pii(min(a[i], b[i]), -1)) - t;
int hi = lower_bound(t, t + k, pii(max(a[i], b[i]), -1)) - t;
int tim = get_max(0, lo, hi);
int xk = get_cnt(0, tim , hi, k);
int delta = 0;
if(turn){
if(tim == -1)delta = xk;
else delta = xk + 1;
}else
delta = xk;
if(delta % 2 == 1)swap(a[i], b[i]);
sum += a[i];
}
cout << sum << endl;
}
