#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int maxn = 2e5 + 10;
const int inf = 1e9 + 10;
int bit[maxn], seg[4*maxn];
void updateBIT( int id ){ for( int i = id; i < maxn; i += i&-i ) bit[i]++; }
int queryBIT( int id ){
int resp = 0;
for( int i = id; i > 0 ; i -= i&-i ) resp += bit[i];
return resp;
}
void updateSEG( int pos, int ini, int fim, int id, int val ){
if( ini > id || id > fim ) return;
if( ini == fim ){ seg[pos] = val; return; }
int mid = ( ini + fim )/2;
int l = 2*pos, r = 2*pos + 1;
updateSEG( l, ini, mid, id, val );
updateSEG( r, mid + 1, fim, id, val );
seg[pos] = max( seg[l], seg[r] );
}
int querySEG( int pos, int ini, int fim, int ki, int kf ){
if( ki > kf ) return 0;
if( fim < ki || kf < ini ) return -inf;
if( ki <= ini && fim <= kf ) return seg[pos];
int mid = ( ini + fim )/2;
int l = 2*pos, r = 2*pos + 1;
int queryl = querySEG( l, ini, mid, ki, kf );
int queryr = querySEG( r, mid + 1, fim, ki, kf );
return max( queryl, queryr );
}
struct card{
int maior, menor, idmaior;
int a, b;
card( int maior = 0, int menor = 0, int a = 0, int b = 0 ) : maior(maior), menor(menor), a(a), b(b) {}
};
vector<card> cartas;
struct evento{
int val, id, tipo;
evento( int v, int i, int t ) : val(v), id(i), tipo(t) {}
bool operator < ( evento e ){
if( val == e.val ) return tipo > e.tipo;
return val > e.val;
}
};
vector<evento> lineSweep;
int main(){
int n, m; cin >> n >> m;
cartas.emplace_back();
for( int i = 1; i <= n; i++ ){
int a, b; cin >> a >> b;
cartas.push_back( card( max( a, b ), min( a, b ), a, b ) );
lineSweep.push_back( evento( max( a, b ), i, 2 ) );
lineSweep.push_back( evento( min( a, b ), i, 1 ) );
}
for( int i = 1; i <= m; i++ ){
int t; cin >> t;
lineSweep.push_back( evento( t, i, 3 ) );
}
sort( lineSweep.begin(), lineSweep.end() );
int cont = 0;
ll resp = 0;
for( evento cur : lineSweep ){
if( cur.tipo == 3 ){
updateBIT( cur.id );
updateSEG( 1, 1, m, ++cont, cur.id );
}
if( cur.tipo == 2 ){
cartas[ cur.id ].idmaior = cont + 1;
}
if( cur.tipo == 1 ){
int last = querySEG( 1, 1, m, cartas[cur.id].idmaior, cont );
int qtd = cont - queryBIT( last );
if( last != 0 ){
if( qtd%2 == 1 ){
resp += (ll)( cartas[cur.id].menor );
}
else{
resp += (ll)( cartas[cur.id].maior );
}
}
else{
if( qtd%2 == 1 ){
resp += (ll)( cartas[cur.id].b );
}
else{
resp += (ll)( cartas[cur.id].a );
}
}
}
}
cout << resp << endl;
}
