#include<bits/stdc++.h>
#include<algorithm>
#include<random>
#include<chrono>
#include<cstdlib>
#include<ctime>
#include<numeric>
#include<vector>
#include<stack>
#include<map>
#include<set>
#include<queue>
#include<iomanip>
#define int long long
#define ll long long
#define L LLONG_MAX
#define fi first
#define se second
#define pii pair<int,int>
#define pll pair<long long,long long>
#define sz(a) ((int)a.size())
#define FOR(i,j,k) for(int i=j;i<=k;i++)
#define REP(i,k,j) for(int i=k;i>=j;i--)
#define FORD(i,a) for(auto i:a)
#define MASK(i) ((1)<<(i))
#define rngdcl mt19937_64 rng(chrono::steady_clock::now().time_asince_epoch().count())
#define random(l,r) ((l)+(rng()%(r-l+1)))
using namespace std;
const int nmax=2e5+1;
int n,m,crr=0;
int a[nmax],b[nmax],c[nmax];
int mx[4*nmax],mn[4*nmax],tree[nmax],ans[nmax],save[nmax];
bool flag=false;
map<int,int> mp;
set<int> s;
void input()
{
cin >> n >> m;
FOR(i,1,n) cin >> a[i] >> b[i];
FOR(i,1,m) cin >> c[i];
}
void build(int id,int l,int r)
{
if(l==r)
{
mx[id]=c[l];
mn[id]=c[l];
return;
}
int mid=(l+r)/2;
build(id*2,l,mid);
build(id*2+1,mid+1,r);
mx[id]=max(mx[id*2],mx[id*2+1]);
mn[id]=min(mn[id*2],mn[id*2+1]);
}
int get(int id,int l,int r,int a,int b)
{
if(l==r) return l;
if(mx[id]<a || b<=mn[id]) return 0;
int mid=(l+r)/2;
if(mn[id*2+1]<b && a<=mx[id*2+1])
{
flag=true;
return get(id*2+1,mid+1,r,a,b);
}
else return get(id*2,l,mid,a,b);
}
void compress()
{
FOR(i,1,m) s.insert(c[i]);
FORD(i,s) mp[i]=++crr;
}
void update(int x)
{
while(x>0)
{
tree[x]++;
x-=(x&-x);
}
}
int get(int x)
{
int ans=0;
while(x<=crr)
{
ans+=tree[x];
x+=(x&-x);
}
return ans;
}
void bit()
{
compress();
REP(i,m,1)
{
ans[i]=get(mp[c[i]]);
update(mp[c[i]]);
}
}
int bs(int x)
{
int l=0,r=n+1;
while(l+1<r)
{
int mid=(l+r)/2;
if(save[mid]>=x) r=mid;
else l=mid;
}
return r;
}
void solve()
{
build(1,1,m);
bit();
int res=0;
FOR(i,1,n)
{
int x=min(a[i],b[i]);
int y=max(a[i],b[i]);
flag=false;
int lst=get(1,1,m,x,y);
if(flag)
{
if(ans[lst]%2==1) res+=x;
else res+=y;
}
else
{
int rm=get(bs(a[i]));
if(rm%2==0) res+=a[i];
else res+=b[i];
}
}
cout << res;
}
signed main()
{
//freopen(".inp", "r", stdin);
//freopen(".out", "w", stdout);
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
input();
solve();
}
