#include <bits/stdc++.h>
using namespace std;
#define rep(i, l, r) for(int i = (l); i < (r); ++i)
#define sz(v) (int)v.size()
#define dbg(x) "[" #x " = " << (x) << "]"
#define all(v) begin(v), end(v)
#define compact(v) v.erase(unique(all(v)), end(v))
#define file(name) if(fopen(name".inp", "r")){ freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
template<typename T>
bool minimize(T& a, const T& b){
if(a > b){
return a = b, true;
}
return false;
}
template<typename T>
bool maximize(T& a, const T& b){
if(a < b){
return a = b, true;
}
return false;
}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
using ll = long long;
using ld = long double;
using ull = unsigned long long;
using vi = vector<int>;
using vl = vector<ll>;
const int MAX = 2e5 + 5;
int N, Q, A[MAX], B[MAX], T[MAX];
vector<int> st[MAX << 2];
template<typename T>
void merge_sort(vector<T>& result, vector<T>& a, vector<T>& b){
int i = 0, j = 0;
while(i < sz(a) || j < sz(b)){
if(i == sz(a)) result.push_back(b[j++]);
else if(j == sz(b)) result.push_back(a[i++]);
else if(a[i] < b[j]) result.push_back(a[i++]);
else result.push_back(b[j++]);
}
}
void build(int id, int l, int r){
if(l == r){
st[id] = {T[l]};
} else{
int mid = l + r >> 1;
build(id << 1, l, mid);
build(id << 1 | 1, mid + 1, r);
merge_sort(st[id], st[id << 1], st[id << 1 | 1]);
}
}
bool exist(int id, int lv, int rv){
return upper_bound(all(st[id]), rv) != lower_bound(all(st[id]), lv);
}
int find_last(int id, int l, int r, int lv, int rv){
if(l == r) return l;
int mid = l + r >> 1;
if(exist(id << 1 | 1, lv, rv)) return find_last(id << 1 | 1, mid + 1, r, lv, rv);
else return find_last(id << 1, l, mid, lv, rv);
}
int find_last(int lv, int rv){
if(exist(1, lv, rv)) return find_last(1, 1, Q, lv, rv);
else return -1;
}
int calc(int id, int lv){
return st[id].end() - lower_bound(all(st[id]), lv);
}
int count_bound(int id, int l, int r, int u, int v, int lv){
if(u <= l && r <= v){
return calc(id, lv);
}
int mid = l + r >> 1;
if(u > mid) return count_bound(id << 1 | 1, mid + 1, r, u, v, lv);
if(mid >= v) return count_bound(id << 1, l, mid, u, v, lv);
return count_bound(id << 1, l, mid, u, v, lv) + count_bound(id << 1 | 1, mid + 1, r, u, v, lv);
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
file("task");
cin >> N >> Q;
for(int i = 1; i <= N; ++i) cin >> A[i] >> B[i];
for(int i = 1; i <= Q; ++i) cin >> T[i];
build(1, 1, Q);
ll ans = 0;
for(int i = 1; i <= N; ++i){
if(A[i] == B[i]){
ans += A[i];
continue;
}
if(A[i] < B[i]){
int last = find_last(A[i], B[i] - 1);
if(last == -1){
int both = count_bound(1, 1, Q, 1, Q, B[i]);
//still at A[i]
if(both & 1){
ans += B[i];
} else{
ans += A[i];
}
} else{
int both = count_bound(1, 1, Q, last, Q, B[i]);
//at B[i] now
if(both & 1){
ans += A[i];
} else{
ans += B[i];
}
}
} else{
swap(A[i], B[i]);
int last = find_last(A[i], B[i] - 1);
if(last == -1){
int both = count_bound(1, 1, Q, 1, Q, B[i]);
//currently at B[i]
if(both & 1){
ans += A[i];
} else{
ans += B[i];
}
} else{
int both = count_bound(1, 1, Q, last, Q, B[i]);
//still at B[i]
if(both & 1){
ans += A[i];
} else{
ans += B[i];
}
}
}
}
cout << ans << '\n';
return 0;
}
