/*input
5 3
4 6
9 1
8 8
4 2
3 7
8
2
9
*/
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
//order_of_key #of elements less than x
// find_by_order kth element
typedef unsigned long long int ll;
#define ld long double
#define pii pair<int,int>
typedef tree<pii, null_type, less<pii>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;
#define f first
#define s second
#define pb push_back
#define REP(i,n) for(int i=0;i<n;i++)
#define REP1(i,n) for(int i=1;i<=n;i++)
#define FILL(n,x) memset(n,x,sizeof(n))
#define ALL(_a) _a.begin(),_a.end()
#define sz(x) (int)x.size()
const ll maxn=6e5+5;
const ll maxlg=__lg(maxn)+2;
const ll INF64=4e18;
const int MOD=1e9+7;
const int INF=0x3f3f3f3f;
const ld PI=acos(-1);
const ld eps=1e-9;
#define lowb(x) x&(-x)
#define MNTO(x,y) x=min(x,(__typeof__(x))y)
#define MXTO(x,y) x=max(x,(__typeof__(x))y)
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()), c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
#define GET_POS(c,x) (lower_bound(c.begin(),c.end(),x)-c.begin())+1
template<typename T1,typename T2>
ostream& operator<<(ostream& out,pair<T1,T2> P){
out<<P.f<<' '<<P.s;
return out;
}
template<typename T>
ostream& operator<<(ostream& out,vector<T> V){
REP(i,sz(V)) out<<V[i]<<((i!=sz(V)-1)?" ":"");
return out;
}
ll mult(ll a,ll b){
if(a<0) a+=MOD;
return (a*b)%MOD;
}
ll mypow(ll a,ll b){
if(b<=0) return 1;
ll res=1LL;
while(b){
if(b&1) res=mult(res,a);
a=mult(a,a);
b>>=1;
}
return res;
}
struct seg{
int seg[4*maxn];
void upd(int idx,int l,int r,int p,int x){
if(r<p or l>p) return;
if(l==r){
seg[idx]=x;
return;
}
int mid=(l+r)/2;
upd(idx*2,l,mid,p,x);
upd(idx*2+1,mid+1,r,p,x);
seg[idx]=max(seg[idx*2],seg[idx*2+1]);
}
int query(int idx,int l,int r,int ql,int qr){
if(r<ql or l>qr) return 0;
if(ql<=l and r<=qr) return seg[idx];
int mid=(l+r)/2;
return max(query(idx*2,l,mid,ql,qr),query(idx*2+1,mid+1,r,ql,qr));
}
}seg;
int bit[maxn];
void upd(int x){
while(x<maxn){
bit[x]++;
x+=lowb(x);
}
}
int query(int x){
int ans=0;
while(x){
ans+=bit[x];
x-=lowb(x);
}
return ans;
}
int a[maxn],b[maxn],arr[maxn],lst[maxn];
int ans[maxn];
int32_t main(){
ios::sync_with_stdio(false),cin.tie(0);
int n,q;
cin>>n>>q;
vector<int> v;
REP(i,n) cin>>a[i]>>b[i],v.pb(a[i]),v.pb(b[i]);
REP(i,q) cin>>arr[i],v.pb(arr[i]);
SORT_UNIQUE(v);
REP(i,n) a[i]=GET_POS(v,a[i]),b[i]=GET_POS(v,b[i]);
REP(i,q) arr[i]=GET_POS(v,arr[i]);
REP(i,q){
seg.upd(1,1,sz(v),arr[i],i+1);
}
vector<pii> vv;
REP(i,n){
lst[i]=seg.query(1,1,sz(v),min(a[i],b[i]),max(a[i],b[i])-1);
vv.pb({lst[i],i});
}
sort(ALL(vv));
reverse(ALL(vv));
int p=q-1;
for(auto x:vv){
while(p>=x.f){
upd(arr[p]);
--p;
}
int cnt=query(sz(v))-query(b[x.s]-1);
int i=x.s;
//cout<<i<<' '<<cnt<<'\n';
if(x.f and a[i]<b[i]) ++cnt;
if(cnt%2) ans[i]=b[i];
else ans[i]=a[i];
}
ll sum=0;
REP(i,n) sum+=v[ans[i]-1];
cout<<sum;
}
