// Born_To_Laugh - Hughie Do
#include <bits/stdc++.h>
#define alle(AC) AC.begin(), AC.end()
#define fi first
#define se second
using namespace std;
typedef long long ll;
[[maybe_unused]] const int MOD = 998244353, INF = 1e9 + 7;
const int maxn = 2e5 + 10;
struct PerFen
{
int n, time;
vector<vector<pair<int, int>>> bit;
void init(int len){
n = len;
time = 0;
bit.assign(len + 1, {{0, 0}});
}
int upd(int pos, int val){
time++;
for(; pos<=n; pos += pos & -pos){
bit[pos].push_back({time, bit[pos].back().se + val});
}
return time;
}
int qr(int pos, int tim){
int ans = 0;
for(; pos>0; pos -= pos & -pos){
int id = upper_bound(alle(bit[pos]), make_pair(tim, INF)) - bit[pos].begin() - 1;
ans += bit[pos][id].se;
}
return ans;
}
int qr(int l, int r, int pos){
if(l > r) return 0;
return qr(r, pos) - qr(l - 1, pos);
}
};
int n, k;
int a[maxn], b[maxn], t[maxn];
int prefsum[maxn * 2];
int ver[maxn];
PerFen ft;
vector<int> temp;
void solve(){
cin >> n >> k;
for(int i=1; i<=n; ++i){
cin >> a[i] >> b[i];
temp.push_back(a[i]);
temp.push_back(b[i]);
}
for(int i=1; i<=k; ++i){
cin >> t[i];
temp.push_back(t[i]);
}
sort(alle(temp));
temp.erase(unique(alle(temp)), temp.end());
ft.init(temp.size() + 5);
for(int i=1; i<=n; ++i){
a[i] = lower_bound(alle(temp), a[i]) - temp.begin() + 1;
b[i] = lower_bound(alle(temp), b[i]) - temp.begin() + 1;
}
for(int i=1; i<=k; ++i){
t[i] = lower_bound(alle(temp), t[i]) - temp.begin() + 1;
}
for(int i=k; i>=1; --i) ver[i] = ft.upd(t[i], 1);
auto check = [&](int x, int a, int b) -> bool {
return ft.qr(a, b - 1, ver[x]) == 0;
};
ll ans = 0;
for(int i=1; i<=n; ++i){
if(ft.qr(min(a[i], b[i]), max(a[i], b[i]) - 1, ver[1]) == 0){
int num = ft.qr(max(a[i], b[i]), ft.n, ver[1]);
if(num & 1){
ans += temp[b[i] - 1];
}
else ans += temp[a[i] - 1];
continue;
}
int lo = 1, hi = k;
int res = hi;
while(hi >= lo){
int mid = (lo + hi) >> 1;
if(check(mid, min(a[i], b[i]), max(a[i], b[i]))){
res = mid;
hi = mid - 1;
}
else lo = mid + 1;
}
int num = ft.qr(max(a[i], b[i]), ft.n, ver[res]);
if(num & 1){
ans += temp[min(a[i], b[i]) - 1];
}
else{
ans += temp[max(a[i], b[i]) - 1];
}
}
cout << ans << '\n';
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
solve();
}
