#include <bits/stdc++.h>
using namespace std;
const int LIM = 2e5 + 5;
const int LG = 30;
int n, q;
int a[LIM], b[LIM], dir[LIM], c[LIM], d[LIM];
int st[LIM * LG], L[LIM * LG], R[LIM * LG], node = 0, vers[LIM];
int up(int old, int l, int r, int pos, int val){
int cur = ++ node;
if(l == r){
st[cur] = st[old] + val;
return cur;
}
int mid = (l + r) >> 1;
if(pos <= mid){
R[cur] = R[old];
L[cur] = up(L[old], l, mid, pos, val);
} else{
L[cur] = L[old];
R[cur] = up(R[old], mid + 1, r, pos, val);
}
st[cur] = st[L[cur]] + st[R[cur]];
return cur;
}
int get(int id, int l, int r, int u, int v){
if(l > v || r < u) return 0;
if(l >= u && r <= v) return st[id];
int mid = (l + r) >> 1;
return get(L[id], l, mid, u, v) + get(R[id], mid + 1, r, u, v);
}
signed main(){
ios_base::sync_with_stdio(0); cin.tie(0);
#define kieuoanh "joi14_fortune_telling2"
if(fopen(kieuoanh".inp", "r")){
freopen(kieuoanh".inp", "r", stdin); freopen(kieuoanh".out", "w", stdout);
}
cin >> n >> q;
vector <int> values;
for(int i = 1; i <= n; i++){
cin >> a[i] >> b[i];
values.push_back(a[i]);
values.push_back(b[i]);
c[i] = a[i], d[i] = b[i];
if(a[i] > b[i]){
swap(a[i], b[i]);
dir[i] = 1;
}
}
vector <int> num_query(q + 2, 0);
for(int i = 1; i <= q; i++)
cin >> num_query[i];
// tìm query cuối cùng ai <= x < bi
for(int i = 1; i <= q; i++){
values.push_back(num_query[i]);
}
sort(values.begin(), values.end());
values.resize(unique(values.begin(), values.end()) - values.begin());
for(int i = 1; i <= n; i++){
a[i] = upper_bound(values.begin(), values.end(), a[i]) - values.begin();
b[i] = upper_bound(values.begin(), values.end(), b[i]) - values.begin();
}
for(int i = 1; i <= q; i++){
num_query[i] = upper_bound(values.begin(), values.end(), num_query[i]) - values.begin();
}
int lim = values.size();
for(int i = q; i >= 0; i--){
vers[i] = vers[i + 1];
vers[i] = up(vers[i], 1, lim, num_query[i], 1);
}
long long ans = 0;
for(int i = 1; i <= n; i++){
int l = 0, r = q, pos = 0;
while(l <= r){
int mid = (l + r) >> 1;
if(get(vers[mid], 1, lim, a[i], b[i] - 1)) pos = mid, l = mid + 1;
else r = mid - 1;
}
int cnt = (pos != 0) + get(vers[pos], 1, lim, b[i], lim);
if(pos == 0 && dir[i] == 1) dir[i] ^= 1;
if((cnt + dir[i]) & 1){
ans+= d[i];
}
else{
ans+= c[i];
}
}
cout << ans;
return 0;
}
