#include <bits/stdc++.h>
using namespace std;
constexpr int maxn = 2e5+10, inf = 0x3f3f3f3f;
struct PersistentSegmentTree {
struct Node {
Node *l, *r;
int val;
Node() : l(this), r(this), val(0) {}
};
int t = 0;
Node *root[maxn]; // we have a root for each version of the seg
PersistentSegmentTree() { root[0] = new Node(); }
void upd(int pos) {
++t;
root[t] = upd(root[t-1], 1, inf, pos);
}
Node* upd(Node *node, int i, int j, int pos) { // add v to interval l, r
Node *aq = new Node();
*aq = *node;
aq->val++;
if(i == j) return aq;
int m = (i+j) >> 1;
if(pos <= m)
aq->l = upd(aq->l, i, m, pos);
else
aq->r = upd(aq->r, m+1, j, pos);
return aq;
}
int query(Node *node, int i, int j, int l, int r) { // query the interval [l, r] on this version of the seg
if(i > r || j < l) return 0;
if(i >= l && j <= r) return node->val;
int m = (i+j) >> 1;
return query(node->l, i, m, l, r) + query(node->r, m+1, j, l, r);
}
} segTime;
struct SegmentTree {
int tree[4*maxn], a[maxn]; // we have a root for each version of the seg
void build(int node, int i, int j) {
if(i == j) return (void)(tree[node] = a[i]);
int m = (i+j) >> 1;
build(node<<1, i, m);
build(node<<1|1, m+1, j);
tree[node] = max(tree[node<<1], tree[node<<1|1]);
}
int query(int node, int i, int j, int l, int r) { // query the interval [l, r]
if(i > r || j < l) return 0;
if(i >= l && j <= r) return tree[node];
int m = (i+j) >> 1;
return max(query(node<<1, i, m, l, r), query(node<<1|1, m+1, j, l, r));
}
} segX;
int A[maxn], B[maxn];
pair<int,int> X[maxn];
int main() {
int n, k; scanf("%d %d", &n, &k);
for(int i = 1; i <= n; i++)
scanf("%d %d", A+i, B+i);
for(int i = 1; i <= k; i++) {
int x; scanf("%d", &x); X[i] = {x, i};
segTime.upd(x);
}
sort(X+1, X+k+1);
for(int i = 1; i <= k; i++)
segX.a[i] = X[i].second;
segX.build(1, 1, k);
long long ans = 0;
for(int i = 1; i <= n; i++) {
int a = A[i], b = B[i];
if(a > b) swap(a, b);
// quero achar o evento com o maior tempo tal que o valor dele está contido em [a, b[
int last = 0;
if(a != b) {
int itL = (lower_bound(X+1, X+1+k, pair<int,int>(a, 0)) - X);
int itR = (lower_bound(X+1, X+1+k, pair<int,int>(b, 0)) - X) - 1;
// printf("%d %d -> %d %d\n", a, b, itL, itR);
last = segX.query(1, 1, k, itL, itR);
} else last = 0;
// printf("%d %d -> %d\n", a, b, last);
if(last != 0)
ans += (segTime.query(segTime.root[segTime.t], 1, inf, b, inf) -
segTime.query(segTime.root[last], 1, inf, b, inf)) % 2 == 0 ? b : a;
else
ans += segTime.query(segTime.root[segTime.t], 1, inf, b, inf) % 2 == 0 ? A[i] : B[i];
}
printf("%lld\n", ans);
}
