#include<bits/stdc++.h>
using namespace std;
const int MAXN = 2e5 + 5;
const int MAXX = 2 * MAXN;
int n, k;
int a[MAXN];
int b[MAXN];
int x[MAXN];
int y[MAXN];
vector<int> peal;
int query[MAXN];
int v[MAXN];
int st[4 * MAXX];
bool ck[MAXN];
vector<int> last[MAXN];
int bit[MAXX];
int get(int x)
{
return lower_bound(peal.begin(), peal.end(), x) - peal.begin() + 1;
}
void update(int id, int l, int r, int pos, int val)
{
if (l == r)
{
st[id] = val;
return;
}
int m = (l + r) >> 1;
if (pos <= m)
{
update(id << 1, l, m, pos, val);
}
else
{
update(id << 1 | 1, m + 1, r, pos, val);
}
st[id] = max(st[id << 1], st[id << 1 | 1]);
}
int get(int id, int l, int r, int u, int v)
{
if (v < l || r < u)
{
return 0;
}
if (u <= l and r <= v)
{
return st[id];
}
int m = (l + r) >> 1;
return max(get(id << 1, l, m, u, v), get(id << 1 | 1, m + 1, r, u, v));
}
void update1(int pos, int val)
{
for (int i = pos; i <= MAXX; i += i & -i)
{
bit[i] += val;
}
}
int sum(int pos)
{
int total = 0;
for (int i = pos; i > 0; i -= i & -i)
{
total += bit[i];
}
return total;
}
int range(int l, int r)
{
return sum(r) - sum(l - 1);
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n >> k;
for (int i = 1; i <= n; i++)
{
cin >> a[i] >> b[i];
int minn = min(a[i], b[i]);
int maxx = max(a[i], b[i]);
x[i] = minn;
y[i] = maxx;
peal.push_back(a[i]);
peal.push_back(b[i]);
}
for (int i = 1; i <= k; i++)
{
cin >> query[i];
peal.push_back(query[i]);
}
sort(peal.begin(), peal.end());
peal.erase(unique(peal.begin(), peal.end()), peal.end());
int sz = peal.size();
for (int i = 1; i <= n; i++)
{
x[i] = get(x[i]);
y[i] = get(y[i]);
}
for (int i = 1; i <= k; i++)
{
query[i] = get(query[i]);
}
for (int i = 1; i <= k; i++)
{
v[query[i]] = max(v[query[i]], i);
}
for (int i = 1; i <= sz; i++)
{
update(1, 1, sz, i, v[i]);
}
for (int i = 1; i <= n; i++)
{
int cur = get(1, 1, sz, x[i], y[i] - 1);
last[cur].push_back(i);
}
long long res = 0;
for (int i = k; i >= 1; i--)
{
for (int pos : last[i])
{
int cak = range(y[pos], sz);
if (cak % 2 == 0)
{
if (a[pos] >= b[pos])
{
res += a[pos];
}
else
{
res += b[pos];
}
}
else
{
if (a[pos] >= b[pos])
{
res += b[pos];
}
else
{
res += a[pos];
}
}
}
update1(query[i], 1);
}
for (int pos : last[0])
{
int cur = range(y[pos], sz);
if (cur % 2 == 0)
{
res += a[pos];
}
else
{
res += b[pos];
}
}
cout << res;
}
