#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define ll long long
#define mp(x, y) make_pair(x, y)
#define sz(v) ((int) (v).size())
#define all(v) (v).begin(), (v).end()
#define MASK(i) (1LL << (i))
#define BIT(x, y) (((x) >> (y)) & 1)
#define pb push_back
#define max_rng *max_element
#define min_rng *min_element
#define rep(i, n) for(int i = 1, _n = (n); i <= _n; ++i)
#define forn(i, a, b) for(int i = (a), _b = (b); i <= _b; ++i)
#define ford(i, a, b) for(int i = (a), _b = (b); i >= _b; --i)
template <class X, class Y>
inline bool maximize(X &x, Y y) {
return (x < y ? x = y, true : false);
}
template <class X, class Y>
inline bool minimize(X &x, Y y) {
return (x > y ? x = y, true : false);
}
template <class X>
inline void compress(vector<X> &a) {
sort(all(a));
a.resize(unique(all(a)) - a.begin());
}
int ctz(ll x) { return __builtin_ctzll(x); }
int lg(ll x) { return 63 - __builtin_clzll(x); }
int popcount(ll x) { return __builtin_popcount(x); }
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) {
return l + abs((ll) rng()) % (r - l + 1);
}
const ll oo = (ll) 1e17;
const int inf = (ll) 2e9 + 7, mod = (ll) 1e9 + 7;
const int mxn = 2e5 + 5;
void add(int &x, int y) { x += y; if (x >= mod) x -= mod; }
void sub(int &x, int y) { x -= y; if (x < 0) x += mod; }
int n, k;
int p[mxn];
pair<int, int> a[mxn];
int lst[mxn], side[mxn];
struct Seg {
int n;
vector<int> st;
Seg(int n) : n(n) {
st.resize(2 * n + 5, 0);
}
void upd(int t, int val) {
t += n;
maximize(st[t], val);
while (t > 1) {
t >>= 1;
st[t] = max(st[2 * t], st[2 * t + 1]);
}
}
int get(int l, int r) {
if (l > r) return 0;
int ans = 0;
for (l += n, r += n + 1; l < r; l >>= 1, r >>= 1) {
if (l & 1) maximize(ans, st[l++]);
if (r & 1) maximize(ans, st[--r]);
}
return ans;
}
};
struct fen {
int n;
vector<int> bit;
fen(int n) : n(n) {
bit.resize(n + 1);
}
void upd(int p, int d) {
for (; p <= n; p += p & -p)
bit[p] += d;
return;
}
int get(int p) {
int ans = 0;
for(; p > 0; p -= p & -p) {
ans += bit[p];
}
return ans;
}
int rng(int l, int r) {
if (l > r) return 0;
return get(r) - get(l - 1);
}
};
vector<int> events[mxn];
vector<int> cps;
void zipping() {
rep(i, n) {
cps.pb(a[i].fi);
cps.pb(a[i].se);
}
rep(i, k) cps.pb(p[i]);
compress(cps);
rep(i, n) {
a[i].fi = lower_bound(all(cps), a[i].fi) - cps.begin() + 1;
a[i].se = lower_bound(all(cps), a[i].se) - cps.begin() + 1;
}
rep(i, k) p[i] = lower_bound(all(cps), p[i]) - cps.begin() + 1;
}
int main(void) {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
#define TASK "cquery"
if (fopen(TASK".inp", "r")) {
freopen(TASK".inp", "r", stdin);
freopen(TASK".out", "w", stdout);
}
cin >> n >> k;
rep(i, n) cin >> a[i].fi >> a[i].se;
rep(i, k) cin >> p[i];
zipping();
int m = sz(cps);
rep(i, n) {
if (a[i].fi > a[i].se) {
side[i] = 1;
swap(a[i].fi, a[i].se);
}
}
Seg s(m);
rep(i, k) s.upd(p[i], i);
rep(i, n) {
lst[i] = s.get(a[i].fi, a[i].se - 1);
if (lst[i]) side[i] = 1;
events[lst[i]].pb(i);
}
fen f(m);
ford(i, k, 0) {
for (int j : events[i]) {
int cnt = f.rng(a[j].se, m);
if (cnt & 1) side[j] ^= 1;
}
if (i) f.upd(p[i], 1);
}
ll sum = 0;
rep(i, n) if (side[i])
sum += cps[a[i].se - 1];
else sum += cps[a[i].fi - 1];
cout << sum;
return 0;
}
