#include <bits/stdc++.h>
using namespace std;
const int N=2e5;
int st[12*N+1],n,q;
void update(int x, int low, int hi ,int i, int k)
{
if(low==hi) {st[x]=max(st[x],k); return;}
int mid = low+hi>>1;
if(i<=mid) update(x*2,low,mid,i,k);
else update(x*2+1,mid+1,hi,i,k);
st[x]=max(st[x*2],st[x*2+1]);
}
int getmx(int x, int low ,int hi, int i, int j)
{
if(low>hi || low >j || hi < i) return 0;
if(low>=i && hi<=j) return st[x];
int mid=low+hi>>1;
return max(getmx(x*2,low,mid,i,j), getmx(x*2+1,mid+1,hi,i,j));
}
int bit[3*N+100];
void add(int x)
{
for(; x<=2*n+q+1;x+=x&(-x))
{
bit[x]++;
}
}
int get(int x)
{
int ans=0;
for(; x>0;x-=x&(-x))
{
ans+=bit[x];
}
return ans;
}
int a[N+1],b[N+1],t[N+1];
int ag[N+1],bg[N+1];
int last[N+1];
int id[N+1];
map<int,int> mp;
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> n >> q;
for(int i=1;i<=n;++i)
{
cin >> a[i] >> b[i];
ag[i]=a[i];
bg[i]=b[i];
mp[a[i]]=0;
mp[b[i]]=0;
}
for(int i=1;i<=q;++i)
{
cin >> t[i];
mp[t[i]]=0;
}
int z=0;
for(auto & k : mp) k.second = ++z;
for(int i=1;i<=q;++i)
{
t[i] = mp[t[i]];
update(1,1,2*n+q,t[i],i);
// cout << t[i] << '\n';
}
for(int i=1;i<=n;++i)
{
a[i]=mp[a[i]];
b[i]=mp[b[i]];
last[i]=getmx(1,1,2*n+q,min(a[i],b[i]),max(a[i],b[i])-1);
// cout << a[i] << " " << b[i] << '\n';
//cout << last[i] << " ";
id[i]=i;
}
// cout << '\n';
sort(id+1,id+n+1,[] (int x, int y)
{
return last[x]>last[y];
});
// cout << "WTF";
long long ans=0;
int now=q;
for(int i=1;i<=n;++i)
{
int j = id[i];
// cout << j << " " << last[j] << '\n';
while(now > 0 && now>=last[j])
{
add(t[now]);
// cout << "ADD : " << t[now] << '\n';
now--;
}
// cout << "GET : " << max(a[j],b[j]) << '\n';
int k = get(2*n+q+1) - get(max(a[j],b[j])-1);
// cout << k << '\n';
int cc=0;
if(a[j]>b[j])
{
swap(a[j],b[j]);
swap(ag[j],bg[j]);
cc=1;
}
if(last[j]>0) cc=1;
k%=2;
cc^=k;
if(cc) ans+=(long long)bg[j];
else ans+=(long long)ag[j];
}
cout << ans;
}
