#include <bits/stdc++.h>
using namespace std;
long long n,k,sz;
long long a[200050];
long long b[200050];
long long t[200050];
long long bit[200050];
long long comp[600150];
pair<long long,long long> pos[200050];
vector<long long> v[800250];
void insrt(long long start,long long val,long long i,long long j,long long l,long long r)
{
if(i==l && j==r)
{
v[start].push_back(val);
return;
}
long long m=(l+r)/2;
if(i<m)insrt(2*start,val,i,min(j,m),l,m);
if(j>m)insrt(2*start+1,val,max(i,m),j,m,r);
}
void check(long long start,long long j,long long tt,long long l,long long r)
{
for(long long i=0;i<v[start].size();i++)
{
if(pos[v[start][i]].first<0)
{
pos[v[start][i]].first=j;
}
}
v[start].clear();
if(r-l==1)return;
long long m=(l+r)/2;
if(tt<m)check(2*start,j,tt,l,m);
else
{
check(2*start+1,j,tt,m,r);
}
return;
}
void update(long long x)
{
while(x<=sz)
{
bit[x]++;
x+=x & -x;
}
}
long long sum(long long x)
{
long long rez=0;
while(x>0)
{
rez+=bit[x];
x-=x & -x;
}
return rez;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
//ifstream fin("03-01.txt");
//ofstream fout("01out.txt");
cin >> n >> k;
long long ind=0;
for(long long i=0;i<n;i++)
{
cin >> a[i] >> b[i];
comp[ind++]=a[i];
comp[ind++]=b[i];
}
for(long long i=0;i<k;i++)
{
cin >> t[i];
comp[ind++]=t[i];
}
sort(comp,comp+ind);
sz=unique(comp,comp+ind)-comp;
for(long long i=0;i<n;i++)
{
a[i]=lower_bound(comp,comp+sz,a[i])-comp;
b[i]=lower_bound(comp,comp+sz,b[i])-comp;
pos[i]=make_pair(-1,i);
insrt(1,i,min(a[i],b[i]),max(a[i],b[i]),0,sz);
}
for(long long i=k-1;i>=0;i--)
{
t[i]=lower_bound(comp,comp+sz,t[i])-comp;
check(1,i,t[i],0,sz);
}
sort(pos,pos+n);
reverse(pos,pos+n);
long long cur=k-1;
long long br=0;
long long rez=0;
for(long long i=0;i<n;i++)
{
while(cur>pos[i].first)
{
update(t[cur--]+1);
br++;
}
long long p=pos[i].second;
long long num=(br-sum(max(a[p],b[p])))%2;
long long st=cur>=0 ? (a[p]<b[p] ? 1 : 0) : 0;
rez+=comp[(st + num)%2 ? b[p] : a[p]];
}
cout << rez;
return 0;
}
