#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef double db;
typedef string str;
typedef pair<int,int> pi;
typedef pair<ll,ll> pl;
typedef pair<db,db> pd;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<db> vd;
typedef vector<str> vs;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<pd> vpd;
#define mp make_pair
#define f first
#define s second
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) (x).rbegin(), (x).rend()
#define rsz resize
#define ins insert
#define ft front()
#define bk back()
#define pf push_front
#define pb push_back
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)
const int MOD = 1e9+7; // 998244353;
const int MX = 2e5+5;
const ll INF = 1e18;
const ld PI = acos((ld)-1);
const int xd[4] = {1,0,-1,0}, yd[4] = {0,1,0,-1};
template<class T> bool ckmin(T& a, const T& b) {
return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) {
return a < b ? a = b, 1 : 0; }
int pct(int x) { return __builtin_popcount(x); }
int bit(int x) { return 31-__builtin_clz(x); } // floor(log2(x))
int cdiv(int a, int b) { return a/b+!(a<0||a%b == 0); } // division of a by b rounded up, assumes b > 0
// INPUT
template<class A> void re(complex<A>& c);
template<class A, class B> void re(pair<A,B>& p);
template<class A> void re(vector<A>& v);
template<class A, size_t SZ> void re(array<A,SZ>& a);
template<class T> void re(T& x) { cin >> x; }
void re(db& d) { str t; re(t); d = stod(t); }
void re(ld& d) { str t; re(t); d = stold(t); }
template<class H, class... T> void re(H& h, T&... t) { re(h); re(t...); }
template<class A> void re(complex<A>& c) { A a,b; re(a,b); c = {a,b}; }
template<class A, class B> void re(pair<A,B>& p) { re(p.f,p.s); }
template<class A> void re(vector<A>& x) { trav(a,x) re(a); }
template<class A, size_t SZ> void re(array<A,SZ>& x) { trav(a,x) re(a); }
// TO_STRING
#define ts to_string
template<class A, class B> str ts(pair<A,B> p);
template<class A> str ts(complex<A> c) { return ts(mp(c.real(),c.imag())); }
str ts(bool b) { return b ? "true" : "false"; }
str ts(char c) { str s = ""; s += c; return s; }
str ts(str s) { return s; }
str ts(const char* s) { return (str)s; }
str ts(vector<bool> v) {
bool fst = 1; str res = "{";
F0R(i,sz(v)) {
if (!fst) res += ", ";
fst = 0; res += ts(v[i]);
}
res += "}"; return res;
}
template<size_t SZ> str ts(bitset<SZ> b) {
str res = ""; F0R(i,SZ) res += char('0'+b[i]);
return res; }
template<class T> str ts(T v) {
bool fst = 1; str res = "{";
for (const auto& x: v) {
if (!fst) res += ", ";
fst = 0; res += ts(x);
}
res += "}"; return res;
}
template<class A, class B> str ts(pair<A,B> p) {
return "("+ts(p.f)+", "+ts(p.s)+")"; }
// OUTPUT
template<class A> void pr(A x) { cout << ts(x); }
template<class H, class... T> void pr(const H& h, const T&... t) {
pr(h); pr(t...); }
void ps() { pr("\n"); } // print w/ spaces
template<class H, class... T> void ps(const H& h, const T&... t) {
pr(h); if (sizeof...(t)) pr(" "); ps(t...); }
// DEBUG
void DBG() { cerr << "]" << endl; }
template<class H, class... T> void DBG(H h, T... t) {
cerr << to_string(h); if (sizeof...(t)) cerr << ", ";
DBG(t...); }
#ifdef LOCAL // compile with -DLOCAL
#define dbg(...) cerr << "[" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
#else
#define dbg(...) 42
#endif
// FILE I/O
void setIn(string s) { freopen(s.c_str(),"r",stdin); }
void setOut(string s) { freopen(s.c_str(),"w",stdout); }
void unsyncIO() { ios_base::sync_with_stdio(0); cin.tie(0); }
void setIO(string s = "") {
unsyncIO();
// cin.exceptions(cin.failbit);
// throws exception when do smth illegal
// ex. try to read letter into int
if (sz(s)) { setIn(s+".in"), setOut(s+".out"); } // for USACO
}
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count());
/**
* Description: A set (not multiset!) with support for finding the $n$'th
* element, and finding the index of an element. Change \texttt{null\_type} for map.
* Time: O(\log N)
* Source: KACTL
* Verification: many
*/
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template <class T> using Tree = tree<T, null_type, less<T>,
rb_tree_tag, tree_order_statistics_node_update>;
#define ook order_of_key
#define fbo find_by_order
void treeExample() {
Tree<int> t, t2; t.insert(8);
auto it = t.insert(10).f; assert(it == t.lb(9));
assert(t.ook(10) == 1 && t.ook(11) == 2 && *t.fbo(0) == 8);
t.join(t2); // assuming T < T2 or T > T2, merge t2 into t
}
const int mx = 200005;
int N, K;
int A[mx];
int B[mx];
int T[mx];
int qans[mx];
bool start[mx]; //start as maximum?
set<pi> s1; //(pos, val)
set<pi> s2; //(val, pos)
void INS(int pos, int val){ //insert
if(sz(s1) == 0){
s1.ins(mp(pos, val));
s2.ins(mp(val, pos));
return;
}
auto it = s1.lb(mp(pos, 0));
if(it != s1.end() && it->s >= val){
return;
}
while(sz(s1)){
auto it = s1.lb(mp(pos, 0));
if(it == s1.begin()) break;
if(prev(it)->s <= val){
pi a = *(prev(it));
s1.erase(a);
swap(a.f, a.s);
s2.erase(a);
}
}
s1.ins(mp(pos, val));
s2.ins(mp(val, pos));
return;
}
int getIND(int val){ //rightmost position of element > val
if(sz(s2) == 0) return -1;
auto it = s2.lb(mp(val, MOD));
if(it == s2.end()) return -1;
return it->s;
}
int main() {
setIO();
cin >> N >> K;
vpi bs;
for(int i = 1; i <= N; i++){
cin >> A[i] >> B[i];
A[i] = -A[i];
B[i] = -B[i];
if(A[i] > B[i]){
start[i] = 1;
swap(A[i], B[i]);
}
bs.pb(mp(B[i], i));
}
sort(all(bs));
vpi vals;
for(int j = 1; j <= K; j++){
cin >> T[j];
T[j] = -T[j];
vals.pb(mp(T[j], j));
}
sort(all(vals));
int vind = 0;
for(auto u: bs){
int qind = u.s;
int a = A[qind];
int b = B[qind];
while(vind < sz(vals) && vals[vind].f <= b){
//insert vals[vind].f;
int ind = vals[vind].s;
int val = T[ind];
INS(ind, val);
vind++;
}
qans[qind] = getIND(a);
}
vpi queries;
for(int i = 1; i <= N; i++){
if(qans[i] != -1){
start[i] = 0; //reset to min
}
if(qans[i] == -1) qans[i] = 0;
queries.pb(mp(qans[i]+1, i)); // pos >= .f, ind
}
sort(queries.rbegin(), queries.rend());
Tree<pi> tr; //mp(T[j], j)
int curtind = K;
for(int i = 1; i <= N; i++){
dbg(i, start[i]);
}
for(auto u: queries){
int ind = u.s;
int pos = u.f;
int bound = A[ind];
while(curtind > 0 && curtind >= pos){
tr.ins(mp(T[curtind], curtind));
curtind--;
}
int num = tr.order_of_key(mp(bound, MOD));
//dbg(ind, pos, bound, num);
bool a = num % 2;
start[ind]^=a;
}
for(int i = 1; i <= N; i++){
dbg(i, start[i]);
}
ll ans = 0;
for(int i = 1; i <= N; i++){
if(start[i] == 0){
ans+=ll(A[i]);
}
else ans+=ll(B[i]);
}
ps(-ans);
// you should actually read the stuff at the bottom
}
/* stuff you should look for
* int overflow, array bounds
* special cases (n=1?)
* do smth instead of nothing and stay organized
* WRITE STUFF DOWN
*/
