#include<stdio.h>
#include<algorithm>
#include<vector>
using namespace std;
int n, k;
int a[200100], b[200100], q[200100];
int ia[200100], ib[200100];
int all[400100], m;
struct idxtree {
int tree[1050000];
int key;
void init(int n) {
key = 1;
while(key<n) key*=2;
for (int i=0;i<key*2;i++) tree[i] = -1;
}
void update(int idx, int val) {
idx+=key;
tree[idx] = max(tree[idx],val);
idx/=2;
while(idx>0) {
tree[idx] = max(tree[idx*2],tree[idx*2+1]);
idx/=2;
}
}
int query(int s, int e) {
int res = -1;
s+=key;
e+=key;
while(s<=e) {
if (s%2==1) res = max(res,tree[s++]);
if (e%2==0) res = max(res,tree[e--]);
s >>= 1;
e >>= 1;
}
return res;
}
} it;
struct vectortree {
vector<int> tree[550000];
int key;
void init(int n) {
key = 1;
while(key<n) key*=2;
for (int i=0;i<key*2;i++) tree[i].clear();
}
void update(int idx, int val) {
idx+=key;
tree[idx].push_back(val);
}
void merge() {
int i;
for (i=key-1;i>0;i--) {
int l = 2*i, r = 2*i+1;
int kl = 0, kr = 0;
while(kl<tree[l].size()&&kr<tree[r].size()) {
if (tree[l][kl]<tree[r][kr]) tree[i].push_back(tree[l][kl++]);
else tree[i].push_back(tree[r][kr++]);
}
if (kl<tree[l].size()) for (;kl<tree[l].size();kl++) tree[i].push_back(tree[l][kl]);
if (kr<tree[r].size()) for (;kr<tree[r].size();kr++) tree[i].push_back(tree[r][kr]);
}
}
int query(int s, int e, int val) { // [s,e] 에서 val 이상의 개수
int res = 0;
s+=key;
e+=key;
while(s<=e) {
if (s%2==1) {res += tree[s].end()-lower_bound(tree[s].begin(),tree[s].end(),val);s++;}
if (e%2==0) {res += tree[e].end()-lower_bound(tree[e].begin(),tree[e].end(),val);e--;}
s >>= 1;
e >>= 1;
}
return res;
}
} vit;
void process() {
int i;
for (i=0;i<n;i++) {
all[i*2] = a[i];
all[i*2+1] = b[i];
}
sort(all,all+2*n);
m = unique(all,all+2*n)-all;
for (i=0;i<n;i++) {
ia[i] = lower_bound(all,all+m,a[i])-all;
ib[i] = lower_bound(all,all+m,b[i])-all;
}
it.init(m+2);
vit.init(k+2);
for (i=0;i<k;i++) {
int iq = upper_bound(all,all+m,q[i])-all-1;
vit.update(i,iq);
if (iq==-1) continue;
it.update(iq,i);
}
vit.merge();
long long sum = 0;
for (i=0;i<n;i++) {
int idx = it.query(min(ia[i],ib[i]),max(ia[i],ib[i])-1);
int res = vit.query(idx+1,k-1,max(ia[i],ib[i]));
if (idx==-1||a[i]>=b[i]) {
if (res%2==0) sum+=(long long)a[i];
else sum+=(long long)b[i];
}
else {
if (res%2==0) sum+=(long long)b[i];
else sum+=(long long)a[i];
}
}
printf("%lld\n",sum);
}
void input() {
int i;
scanf("%d %d",&n,&k);
for (i=0;i<n;i++) scanf("%d %d",&a[i],&b[i]);
for (i=0;i<k;i++) scanf("%d",&q[i]);
}
int main() {
input();
process();
return 0;
}
