// be name khoda
#include<bits/stdc++.h>
using namespace std;
#define F first
#define S second
//#define mp make_pair
typedef long long ll;
#pragma GCC optimize("Ofast")
const int maxn = 2e5+10;
//const int mod = 1e9+7;
//const ll inf = 1e9+10;
int seg[maxn*20], L[maxn*20], R[maxn*20], n;
int root[maxn], lst;
void up(int v, int nw, int pos, int tl = 1, int tr = n)
{
seg[nw] = seg[v] + 1;
if(tl == tr) return;
int tm = (tl + tr) >> 1;
if(pos <= tm)
{
L[nw] = ++lst; R[nw] = R[v];
up(L[v], L[nw], pos, tl, tm);
}
else
{
R[nw] = ++lst; L[nw] = L[v];
up(R[v], R[nw], pos, tm+1, tr);
}
}
int qu(int v, int l, int r, int tl = 1, int tr = n)
{
if(l > r) return 0;
if(tl == l && tr == r) return seg[v];
int tm = (tl + tr) >> 1;
return qu(L[v], l, min(tm,r), tl, tm) +
qu(R[v], max(tm+1,l), r, tm+1, tr);
}
int qu2(int v1, int v2, int tl = 1, int tr = n)
{
if(tl == tr)
{
if(seg[v1] == seg[v2]) return tl;
else return tl+1;
}
int tm = (tl + tr) >> 1;
if(seg[R[v1]] == seg[R[v2]])
return qu2(L[v1], L[v2], tl, tm);
else
return qu2(R[v1], R[v2], tm+1, tr);
}
vector<pair<int,int>> ve;
int QU(int x, int l, int r)
{
int X = lower_bound(ve.begin(), ve.end(), make_pair(x,0)) - ve.begin();
return qu(root[X], l, r);
}
int A[maxn], B[maxn];
signed main()
{
//ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
int m; scanf("%d%d", &m, &n);
for(int i = 1; i <= m; i++) scanf("%d%d", A+i, B+i);
for(int i = 1, t; i <= n; i++)
{scanf("%d", &t); ve.push_back({t,i});}
sort(ve.begin(), ve.end());
for(int i = ve.size()-1; i >= 0; i--)
{
int pos = ve[i].S;
root[i] = ++lst;
up(root[i+1], root[i], pos);
}
ll ans = 0;
for(int i = 1, a, b; i <= m; i++)
{
a = A[i], b = B[i];
int lo = 0, hi = n+1;
int Xa = lower_bound(ve.begin(), ve.end(), make_pair(a,0)) - ve.begin();
int Xb = lower_bound(ve.begin(), ve.end(), make_pair(b,0)) - ve.begin();
hi = qu2(root[Xa], root[Xb]);
int X = qu(root[Xa], hi, n);
if(QU(min(a,b), 1, hi-1) == 0)
{
if(X&1) ans += b;
else ans += a;
}
else
{
if(X&1) ans += min(a,b);
else ans += max(a,b);
}
}
printf("%lld", ans);
}
