#include <bits/stdc++.h>
using namespace std;
#define TASK "long"
#define fi first
#define se second
#define ll long long
#define pb push_back
#define ALL(x) (x).begin(), (x).end()
#define GETBIT(mask, i) ((mask) >> (i) & 1)
#define MASK(i) ((1LL) << (i))
#define SZ(x) ((int)(x).size())
#define mp make_pair
#define CNTBIT(mask) __builtin_popcount(mask)
template<class X, class Y> bool maximize(X &x, Y y){ if (x < y) {x = y; return true;} return false;};
template<class X, class Y> bool minimize(X &x, Y y){ if (x > y) {x = y; return true;} return false;};
typedef pair<int, int> ii;
const int N = 2e5 + 5;
const int inf = 1e9 + 7;
const long long INF = (long long)1e18 + 7;
const int mod = 1e9 + 7;
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 mul(int x, int y) {return 1LL * x * y % mod;}
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
long long rnd(long long l, long long r) {
return uniform_int_distribution<long long>(l, r)(rd);
}
// -----------------------------------------//
struct FenwickMax {
int n;
vector<int> v;
FenwickMax(int _n = 0) {
n = _n;
v.assign(n + 2, 0);
}
void update(int x, int c) {
for(; x > 0; x -= x & -x) v[x] = max(v[x], c);
}
int get(int x) {
int ans = 0;
for(; x <= n; x += x & -x) ans = max(ans, v[x]);
return ans;
}
} fw1;
struct Fenwick {
int n;
vector<int> v;
Fenwick(int _n = 0) {
n = _n;
v.assign(n + 2, 0);
}
void update(int x, int c) {
for(; x <= n; x += x & -x) v[x] += c;
}
int get(int x) {
int ans = 0;
for(; x > 0; x -= x & -x) ans += v[x];
return ans;
}
int get(int l, int r) {
return get(r) - get(l - 1);
}
} fw;
int n, q;
int pos[N];
vector<int> val;
pair<int, int> a[N], queries[N];
void read() {
cin >> n >> q;
for(int i = 1; i <= n; i++) cin >> a[i].fi >> a[i].se;
for(int i = 1; i <= q; i++) {
cin >> queries[i].fi;
queries[i].se = i;
}
}
void sub1() {
// sort(queries + 1, queries + q + 1);
vector<int> on(n + 1, 0);
for(int iter = 1; iter <= q; iter++) {
int lim = queries[iter].fi;
for(int i = 1; i <= n; i++) {
int x = (on[i] ? a[i].se : a[i].fi);
if (x <= lim) on[i] ^= 1;
}
}
long long ans = 0;
for(int i = 1; i <= n; i++) ans += (on[i] ? a[i].se : a[i].fi);
cout << ans;
}
int getPos(int x) {
return lower_bound(ALL(val), x) - val.begin() + 1;
}
void solve() {
// if (max(n, q) <= 1000) {
// sub1();
// return;
// }
for(int i = 1; i <= n; i++) val.push_back(min(a[i].fi, a[i].se));
for(int i = 1; i <= q; i++) val.push_back(queries[i].fi);
sort(ALL(val));
for(int i = 1; i <= n; i++) pos[i] = i;
sort(pos + 1, pos + n + 1, [&](int x, int y) {
return max(a[x].fi, a[x].se) < max(a[y].fi, a[y].se);
});
sort(queries + 1, queries + q + 1);
fw = Fenwick(q);
fw1 = FenwickMax(SZ(val));
for(int i = 1; i <= q; i++) fw.update(i, 1);
long long ans = 0;
for(int i = 1, j = 1; i <= n; i++) {
int p = pos[i];
int mx = max(a[p].fi, a[p].se);
cerr << "i: " << p << endl;
while(j <= q && queries[j].fi < mx) {
// cerr << queries[j].fi << ' ' << queries[j].se << endl;
fw.update(queries[j].se, -1);
fw1.update(getPos(queries[j].fi), queries[j].se);
++j;
}
int tmp = fw1.get(getPos(min(a[p].fi, a[p].se)));
if (tmp == 0) {
int x = fw.get(q);
if (x & 1) ans += a[p].se;
else ans += a[p].fi;
}
else {
int x = fw.get(tmp, q);
if (x & 1) ans += min(a[p].fi, a[p].se);
else ans += max(a[p].fi, a[p].se);
}
// cerr << "ANS: " << ans << endl;
}
cout << ans;
}
signed main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
if (fopen(TASK".inp", "r")) {
freopen(TASK".inp", "r", stdin);
freopen(TASK".out", "w", stdout);
}
int test = 1;
// cin >> test;
while(test--) {
read();
solve();
}
return 0;
}
