#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
#define long long long
#define pii pair<int, int>
#define x first
#define y second
const int N = 2e5+5;
int n, k;
long ans;
vector<pii> que;
vector<int> coor;
struct item {
int v;
item *l, *r;
item() {}
item(int v, item *l, item *r) : v(v), l(l), r(r) {}
};
using pitem = item*;
#define vari pitem p, int l = 0, int r = coor.size()
#define mid ((l + r) >> 1)
#define lb p->l, l, mid
#define rb p->r, mid+1, r
pitem newleaf(int v) { return new item(v, nullptr, nullptr); }
pitem newpar(pitem l, pitem r) { return new item(l->v + r->v, l, r); }
pitem build(int l = 0, int r = coor.size()) {
if(l == r) return newleaf(0);
return newpar(build(l, mid), build(mid+1, r));
}
pitem update(int x, vari) {
if(l == r) return newleaf(p->v + 1);
if(x <= mid) return newpar(update(x, lb), p->r);
else return newpar(p->l, update(x, rb));
}
int query(int x, vari) {
if(x <= l) return p->v;
if(x > mid) return query(x, rb);
return query(x, lb) + query(x, rb);
}
int A[N];
pitem ver[N];
int f(int m, int v) {
return query(lower_bound(all(coor), v) - coor.begin(), ver[m]);
}
int main() {
scanf("%d %d", &n, &k);
for(int i = 0, a, b; i < n; ++i) {
scanf("%d %d", &a, &b);
que.emplace_back(a, b);
}
coor.resize(1);
for(int i = 1; i <= k; ++i) {
scanf("%d", A+i);
coor.emplace_back(A[i]);
}
sort(all(coor));
coor.resize(unique(all(coor)) - coor.begin());
ver[k+1] = build();
for(int i = k; ~i; --i) ver[i] = update(lower_bound(all(coor), A[i]) - coor.begin(), ver[i+1]);
for(auto x : que) {
int a, b; tie(a, b) = x;
int l = 0, r = k;
while(l < r) {
int m = (l + r + 1) >> 1;
if(f(m, a) != f(m, b)) l = m;
else r = m-1;
}
if(l == 0) ans += f(0, a) & 1 ? b : a;
else ans += f(l, max(a, b)) & 1 ? min(a, b) : max(a, b);
}
printf("%lld\n", ans);
}
