#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int MAXN = 2e5;
int N, M;
pii A[MAXN+10];
int B[MAXN+10];
ll ans;
vector<int> tree[MAXN*4+10];
void init(int node, int tl, int tr)
{
if(tl==tr)
{
tree[node].push_back(B[tl]);
return;
}
int mid=tl+tr>>1;
init(node*2, tl, mid);
init(node*2+1, mid+1, tr);
tree[node].resize(tree[node*2].size()+tree[node*2+1].size());
merge(tree[node*2].begin(), tree[node*2].end(), tree[node*2+1].begin(), tree[node*2+1].end(), tree[node].begin());
}
int query1(int node, int tl, int tr, int l, int r)
{
if(tl==tr) return tl;
int mid=tl+tr>>1;
if(lower_bound(tree[node*2+1].begin(), tree[node*2+1].end(), r)-lower_bound(tree[node*2+1].begin(), tree[node*2+1].end(), l)) return query1(node*2+1, mid+1, tr, l, r);
else return query1(node*2, tl, mid, l, r);
}
int query2(int node, int tl, int tr, int l, int r, int k)
{
if(r<tl || tr<l) return 0;
if(l<=tl && tr<=r) return tree[node].end()-lower_bound(tree[node].begin(), tree[node].end(), k);
int mid=tl+tr>>1;
return query2(node*2, tl, mid, l, r, k)+query2(node*2+1, mid+1, tr, l, r, k);
}
int main()
{
int i, j;
scanf("%d%d", &N, &M);
for(i=1; i<=N; i++) scanf("%d%d", &A[i].first, &A[i].second);
for(i=1; i<=M; i++) scanf("%d", &B[i]);
init(1, 1, M);
for(i=1; i<=N; i++)
{
int l=A[i].first, r=A[i].second;
if(l>r) swap(l, r);
int t=lower_bound(tree[1].begin(), tree[1].end(), r)-lower_bound(tree[1].begin(), tree[1].end(), l);
if(t)
{
int p=query1(1, 1, M, l, r);
int q=query2(1, 1, M, p+1, M, r);
if(q%2) ans+=l;
else ans+=r;
}
else
{
int q=query2(1, 1, M, 1, M, r);
if(q%2) ans+=A[i].second;
else ans+=A[i].first;
}
}
printf("%lld\n", ans);
}
