#include<bits/stdc++.h>
using namespace std;
bool M1;
#define PI 3.14159265358979323846
#define sz(a) (int)a.size()
#define all(x) x.begin(),x.end()
#define ii pair<int,int>
#define iii pair<int,ii>
#define iv pair<ii,ii>
#define se second
#define fi first
#define ffi fi.fi
#define sfi se.fi
#define sse se.se
#define fse fi.se
#define lt(i, c, d) for(int i = c; i <= d; ++i)
#define fl(i, c, d) for(int i = d; i >= c; --i)
#define pb push_back
#define emb emplace_back
#define emf emplace_front
#define em emplace
#define look_memory cerr<<abs(&M2-&M1)/1024.0/1024<<'\n'
#define look_time cerr << "TIME : " << clock() * 0.001 << "s" <<'\n'
const int N=1e6+5,lg=30,mod=1e9+7;
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
int Rand(int u,int v){
return u+rd()%(v-u+1);
}
int dx[]={1,0,-1,0,1,1,-1,-1};
int dy[]={0,-1,0,1,1,-1,1,-1};
int node,query,a[N],t[N],b[N],ans[N];
long long sum;
ii res[N];
vector<int>nen;
struct segmax {
int n;
vector<int> st, lazy;
segmax() {};
segmax(int _n): n(_n), st(n * 4 + 5, 0), lazy(n * 4 + 5, 0) {};
void build(int id, int l, int r) {
if (l == r) {
st[id] = a[l];
return;
}
int mid = (l + r) >> 1;
build(id << 1, l, mid);
build(id << 1 | 1, mid + 1, r);
st[id] = max(st[id << 1], st[id << 1 | 1]);
}
void down(int id) {
if (lazy[id] == 0) return;
lazy[id << 1] = lazy[id];
lazy[id << 1 | 1] = lazy[id];
st[id << 1] = lazy[id];
st[id << 1 | 1] = lazy[id];
lazy[id] = 0;
}
void update(int id, int l, int r, int u, int v, int val) {
if (r < u || l > v) return;
if (l >= u && r <= v) {
st[id] = val;
lazy[id] = val;
return;
}
down(id);
int mid = (l + r) >> 1;
update(id << 1, l, mid, u, v, val);
update(id << 1 | 1, mid + 1, r, u, v, val);
st[id] = max(st[id << 1], st[id << 1 | 1]);
}
int get(int id, int l, int r, int u, int v) {
if (r < u || l > v) return 0;
if (l >= u && r <= v) return st[id];
down(id);
int mid = (l + r) >> 1;
return max(get(id << 1, l, mid, u, v), get(id << 1 | 1, mid + 1, r, u, v));
}
};
struct segsum {
int n;
vector<int> st, lazy;
segsum() {};
segsum(int _n): n(_n), st(n * 4 + 5, 0), lazy(n * 4 + 5, 0) {};
void build(int id, int l, int r) {
if (l == r) {
st[id] = a[l];
return;
}
int mid = (l + r) >> 1;
build(id << 1, l, mid);
build(id << 1 | 1, mid + 1, r);
st[id] = st[id << 1] + st[id << 1 | 1];
}
void down(int id, int l, int r) {
if (lazy[id] == 0) return;
int mid = (l + r) >> 1;
lazy[id << 1] += lazy[id];
lazy[id << 1 | 1] += lazy[id];
st[id << 1] += lazy[id] * (mid - l + 1);
st[id << 1 | 1] += lazy[id] * (r - mid);
lazy[id] = 0;
}
void update(int id, int l, int r, int u, int v, int val) {
if (r < u || l > v) return;
if (l >= u && r <= v) {
st[id] += val * (r - l + 1);
lazy[id] += val;
return;
}
down(id, l, r);
int mid = (l + r) >> 1;
update(id << 1, l, mid, u, v, val);
update(id << 1 | 1, mid + 1, r, u, v, val);
st[id] = st[id << 1] + st[id << 1 | 1];
}
int get(int id, int l, int r, int u, int v) {
if (r < u || l > v) return 0;
if (l >= u && r <= v) return st[id];
down(id, l, r);
int mid = (l + r) >> 1;
return get(id << 1, l, mid, u, v) + get(id << 1 | 1, mid + 1, r, u, v);
}
};
int ne(int u){
return lower_bound(all(nen),u)-nen.begin()+1;
}
bool M2;
void solve(){
cin >> node >> query;
for(int i=1;i<=node;++i){
cin >> a[i] >> b[i];
nen.emb(a[i]);nen.emb(b[i]);
}
for(int i=1;i<=query;++i){
cin >> t[i];
nen.emb(t[i]);
}
sort(all(nen));
nen.erase(unique(all(nen)),nen.end());
int n=sz(nen);
segmax seg(n);
for(int i=1;i<=query;++i){
seg.update(1,1,n,ne(t[i]),ne(t[i]),i);
}
for(int i=1;i<=node;++i){
res[i].fi=seg.get(1,1,n,min(ne(a[i]),ne(b[i])),max(ne(a[i]),ne(b[i]))-1);
res[i].se=i;
// cout <<res[i].fi<<" "<<res[i].se<<'\n';
}
sort(res+1,res+1+node,greater<ii>());
segsum tong(n);
int j=query;
for(int i=1;i<=node;++i){
while(j>res[i].fi){
tong.update(1,1,n,ne(t[j]),ne(t[j]),1);
--j;
}
int u=res[i].se;
bool x=1&tong.get(1,1,n,ne(max(a[u],b[u])),n);
if(res[i].fi==0){
if(x==0)sum+=a[u];
else sum+=b[u];
}
else
if(x==1)sum+=min(a[u],b[u]);
else sum+=max(a[u],b[u]);
// cout <<u<<" "<<x<<" "<<sum<<'\n';
}
cout <<sum;
}
main()
{
srand(time(0));
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
#define task "aws"
if(fopen(task".inp","r")){
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);
}
int t=1;
// cin >> t;
while(t--){
solve();cout<<'\n';
}
look_memory;
look_time;
}
