#pragma GCC optimize("Ofast,unroll-loops")
// #pragma comment(linker, "/stack:200000000")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma,tune=native")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef int ll; typedef long long lol;
typedef long double ld;
typedef pair <ll, ll> pll;
#ifdef SINA
#define dbg(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1> void __f(const char* name, Arg1&& arg1) { cout << name << " : " << arg1 << std::endl; }
template <typename Arg1, typename... Args> void __f (const char* names, Arg1&& arg1, Args&&... args) {
const char* comma = strchr(names + 1, ',');cout.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...); }
#define dbg2(x, j, n) cout<< #x << " : "; output((j), (n), x, 1); cout.flush();
#else
#define dbg(...) 0
#define dbg2(x, j, n) 0
#endif
#define SZ(x) ((ll)((x).size()))
#define File(s, t) freopen(s ".txt", "r", stdin); freopen(t ".txt", "w", stdout);
#define input(j, n, a) for (int _i = (j); _i < (n)+(j); _i++) cin>> a[_i];
#define output(j, n, a, t) for (int _i = (j); _i < (n)+(j); _i++) cout<< a[_i] << (((t) && _i != (n)+(j)-1)? ' ' : '\n');
#define kill(x) return cout<< (x) << endl, 0
#define cl const ll
#define fr first
#define sc second
#define lc (v << 1)
#define rc (lc | 1)
#define mid ((l + r) >> 1)
#define All(x) (x).begin(), (x).end()
cl inf = sizeof(ll) == 4 ? (1e9 + 10) : (3e18), mod = 1e9 + 7, MOD = 998244353;
template <class A,class B> ostream& operator << (ostream& out,const pair<A,B>&a){return out<<'('<<a.first<<", "<<a.second<<')';}
template <class A> ostream& operator << (ostream& out, const vector<A> &a) {
out<< '['; for (int i = -1; ++i < int(a.size());) out<< a[i] << (i + 1 < int(a.size()) ? ", " : ""); return out<<']'; }
template <class T, typename _t = less <T> > using Tree = tree <T, null_type, _t, rb_tree_tag, tree_order_statistics_node_update>;
cl N = 2e5 + 7, NNN = 6e5 + 7;
vector <ll> cmprs; inline ll indx (cl &x) { return upper_bound(All(cmprs), x) - cmprs.begin(); }
ll a [N], b [N], c [N], fen [NNN], n, q;
vector <pll> QR [NNN];
lol ans;
struct segtree1 {
ll l, r, mx;
segtree1 *lt, *rt;
inline segtree1 (cl &L = 1, cl &R = N - 2) : l(L), r(R), mx(0) {}
void build () {
if (l == r) return;
lt = new segtree1 (l, mid);
rt = new segtree1 (mid + 1, r);
lt->build();
rt->build();
mx = max(lt->mx, rt->mx);
}
void modify (cl &pos, cl &x) {
if (l == r) {
mx = x;
return;
}
if (pos <= mid) lt->modify(pos, x);
else rt->modify(pos, x);
mx = max(lt->mx, rt->mx);
}
ll ask (cl &ql, cl &qr) {
if (r < ql || qr < l) return 0;
if (ql <= l && r <= qr) return mx;
return max(lt->ask(ql, qr), rt->ask(ql, qr));
}
} seg;
inline void add (ll i) { for (; i; i -= i & -i) ++fen[i]; }
inline ll ask (ll i) { ll t = 0; for (i = indx(i); i < NNN; i += i & -i) t += fen[i]; return t; }
int main ()
{
ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin>> n >> q;
for (ll i = 1; i <= n; i++) cin>> a[i] >> b[i], cmprs.push_back(a[i]), cmprs.push_back(b[i]);
for (ll i = 1; i <= q; i++) cin>> c[i], cmprs.push_back(c[i]);
sort(All(cmprs)); cmprs.resize(unique(All(cmprs)) - cmprs.begin());
seg.r = SZ(cmprs); seg.build();
for (ll i = 1; i <= q; i++) seg.modify(c[i] = indx(c[i]), i);
for (ll i = 1; i <= n; i++) QR[seg.ask(indx(min(a[i], b[i])), indx(max(a[i], b[i])) - 1)].push_back({max(a[i], b[i]), i});
for (ll i = q; i; i--) {
for (auto &x : QR[i]) {
if (ask(x.fr) & 1) ans += min(a[x.sc], b[x.sc]);
else ans += max(a[x.sc], b[x.sc]);
}
add(c[i]);
}
for (auto &x : QR[0]) ans += (ask(x.fr) & 1 ? b[x.sc] : a[x.sc]);
cout<< ans << endl;
cerr<< "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
return 0;
}
/*
*/
