#include <bits/stdc++.h>
using namespace std;
#define int long long
const int border = 1e9 + 10;
vector<int> minTmp, qnt, e, d;
int create()
{
minTmp.push_back(LONG_LONG_MAX);
qnt.push_back(0);
e.push_back(0);
d.push_back(0);
return qnt.size()-1;
}
void copy(int pos, int novo)
{
minTmp[novo] = minTmp[pos];
qnt[novo] = qnt[pos];
e[novo] = e[pos];
d[novo] = d[pos];
}
int update(int pos, int ini, int fim, int id, int val)
{
if (id < ini || id > fim) return pos;
int novo = create();
copy(pos, novo);
if (ini == fim)
{
qnt[novo]++;
minTmp[novo] = min(minTmp[novo], val);
return novo;
}
int m = (ini + fim) >> 1;
if (id <= m) e[novo] = update(e[novo], ini, m, id, val);
else d[novo] = update(d[novo], m+1, fim, id, val);
qnt[novo] = qnt[e[novo]] + qnt[d[novo]];
minTmp[novo] = min(minTmp[e[novo]], minTmp[d[novo]]);
return novo;
}
pair<int, int> query(int pos, int ini, int fim, int p, int q)
{
if (q < ini || p > fim) return make_pair(0, LONG_LONG_MAX);
if (pos == 0) return make_pair(0, LONG_LONG_MAX);
if (p <= ini && fim <= q) return make_pair(qnt[pos], minTmp[pos]);
int m = (ini + fim) >> 1;
pair<int, int> respE = query(e[pos], ini, m , p, q);
pair<int, int> respD = query(d[pos], m+1, fim, p, q);
return make_pair(respE.first + respD.first, min(respE.second, respD.second));
}
int32_t main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int N, K;
cin >> N >> K;
vector<pair<int, int> > v(N);
for (auto &[x, y] : v) cin >> x >> y;
int ans = 0LL;
// while (v.size() > K) {ans += v.back().first; v.pop_back();}
// reverse(v.begin(), v.end());
// v.emplace_back(0, 0);
// reverse(v.begin(), v.end());
vector<int> Oper(K);
for (auto &x : Oper) cin >> x;
Oper.push_back(-1);
reverse(Oper.begin(), Oper.end());
vector<int> Raiz(K+1);
Raiz[0] = create();
for (int i = 1; i <= K; i++) Raiz[i] = update(Raiz[i-1], 1, border, Oper[i], i);
for (auto [x, y] : v)
{
int resp = 1;
if (x > y) {resp--; swap(x, y);}
auto [qntMeio, minMeio] = query(Raiz[K], 1, border, x, y-1);
if (qntMeio == 0) minMeio = K;
else resp = 0;
if (minMeio == LONG_LONG_MAX) minMeio = K;
auto [qntMaior, minMaior] = query(Raiz[minMeio], 1, border, y, border);
resp += qntMaior;
// cerr << i << " " << qntMeio << " " << minMeio << " " << qntMaior << " " << resp << '\n';
ans += ((resp % 2) ? x : y);
}
cout << ans << '\n';
}
