#include <bits/stdc++.h>
#define N 200010
#define f first
#define s second
using namespace std;
typedef pair<int, int> pii;
typedef long long ll;
vector<int> tree[4*N];
int T[N];
ll resp;
inline void build(int nod, int a, int b)
{
if(a == b)
{
tree[nod].push_back(T[a]);
return;
}
int mid = (a+b)/2;
build(2*nod, a, mid);
build(2*nod + 1, mid + 1, b);
tree[nod] = vector<int> (b - a + 1);
merge(tree[2*nod].begin(), tree[2*nod].end(), tree[2*nod + 1].begin(), tree[2*nod + 1].end(), tree[nod].begin());
}
inline int query_tree(int nod, int a, int b, int i, int j, int X, int Y)
{
if(j < a || i > b) return 0;
if(i <= a && j >= b) return upper_bound(tree[nod].begin(), tree[nod].end(), Y) - lower_bound(tree[nod].begin(), tree[nod].end(), X);
int mid = (a + b)/2, cnt = 0;
if( !(j < a || i > mid)) cnt += query_tree(2*nod, a, (a + b)/2, i, j, X, Y);
if( !(j < mid + 1 || i > b)) cnt += query_tree(2*nod + 1, ((a + b)/2) + 1, b, i, j, X, Y);
return cnt;
}
struct query
{
int A, B, pos, tip;
};
vector< query > Q;
inline bool comp(query L, query R)
{
if(max(L.A, L.B) != max(R.A, R.B)) return max(L.A, L.B) > max(R.A, R.B);
return L.tip > R.tip;
}
int n, m, ans[N], en, st = 200000000;
pii inf_en[N];
inline int bsearch(int A, int B)
{
int ini = 1, fim = m, mid, best = -1;
if(B < A) swap(A, B);
while(fim >= ini)
{
mid = (ini + fim)/2;
int Ai = query_tree(1, 1, m, mid, m, A, B - 1);
if(Ai == 0)
{
best = mid;
fim = mid - 1;
}
else ini = mid + 1;
}
return best;
}
pii v[N];
bool cmp(pii L, pii R)
{
return max(L.f, L.s) < max(R.f, R.s);
}
int main()
{
ios::sync_with_stdio(false); cin.tie(0);
cin>>n>>m;
for(int i = 1, a, b; i <= n; i++)
{
cin>>a>>b;
v[i] = {a, b};
}
for(int i = 1, x; i <= m; i++) cin>>T[i];
build(1, 1, m);
for(int i = 1; i <= n; i++)
{
int db = bsearch(v[i].f, v[i].s);
if(db == -1)
{
if(v[i].f < v[i].s) ans[i] = v[i].s;
else ans[i] = v[i].f;
}
else
{
int A = v[i].f, B = v[i].s;
if(B < A) swap(A, B);
int Ai = query_tree(1, 1, m, db, m, 0, A - 1);
int inf = (2 + (m - db + 1) - Ai)%2;
if(db <= 1)
{
if(inf == 0) ans[i] = v[i].f;
else ans[i] = v[i].s;
}
else if(inf == 0) // ULTIMO CARA FOI UM TRAÇO
{
if(v[i].f < v[i].s) ans[i] = v[i].s;
else ans[i] = v[i].f;
}
else
{
if(inf == 1) // ULTIMO CARA FOI UM INFINITO
{
if (v[i].f < v[i].s) ans[i] = v[i].f;
else ans[i] = v[i].s;
}
}
}
resp += (ll)ans[i];
}
cout<<resp<<"\n";
}
