#include <bits/stdc++.h>
using namespace std;
#define int long long
#define MAX 200001
int a[MAX], b[MAX], q[MAX];
struct Seg
{
int n;
vector<int> ST;
Seg(int _n) : n(_n)
{
ST.assign(1 << (__lg(_n) + 2), -1);
}
void update(int pos, int val)
{
int mid, id = 1, l = 1, r = n;
while (l < r)
{
mid = (l + r) >> 1;
if (pos > mid) id = id << 1 | 1, l = mid + 1;
else id <<= 1, r = mid;
}
ST[id] = val;
while (id > 1)
{
id >>= 1;
ST[id] = max(ST[id << 1], ST[id << 1 | 1]);
}
}
int getpos(int id, int l, int r, int u, int v)
{
if (r < u || v < l) return -1;
if (u <= l && r <= v) return ST[id];
int mid = (l + r) >> 1;
return max(getpos(id << 1, l, mid, u, v), getpos(id << 1 | 1, mid + 1, r, u, v));
}
int getpos(int u, int v)
{
return getpos(1, 1, n, u, v);
}
};
struct waifutree
{
int n;
vector<int> BIT;
waifutree(int _n) : n(_n)
{
BIT.assign(_n + 1, 0);
}
void update(int i, int val)
{
for (; i <= n; i += -i & i) BIT[i] += val;
}
int get(int i)
{
int res = 0;
for (; i > 0; i -= -i & i) res += BIT[i];
return res;
}
};
vector<int> v, res[2 * MAX + MAX], nopar;
bool check[2 * MAX + MAX];
int32_t main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
//freopen("ilight.inp", "r", stdin); freopen("ilight.out", "w", stdout);
int n, k;
cin >> n >> k;
for (int i = 1; i <= n; i++) cin >> a[i] >> b[i], v.push_back(a[i]), v.push_back(b[i]);
for (int i = 1; i <= k; i++) cin >> q[i], v.push_back(q[i]);
sort(v.begin(), v.end());
v.erase(unique(v.begin(), v.end()), v.end());
Seg sg(n * 2 + k);
waifutree fw(n * 2 + k);
for (int i = 1; i <= k; i++)
{
q[i] = lower_bound(v.begin(), v.end(), q[i]) - v.begin() + 1;
sg.update(q[i], i);
}
for (int i = 1; i <= n; i++)
{
a[i] = lower_bound(v.begin(), v.end(), a[i]) - v.begin() + 1;
b[i] = lower_bound(v.begin(), v.end(), b[i]) - v.begin() + 1;
int j = sg.getpos(min(a[i], b[i]), max(a[i], b[i]) - 1);
if (j != -1) res[q[j]].push_back(i);
else nopar.push_back(i);
}
int ans = 0;
for (int i = k; i > 0; i--)
{
if (!check[q[i]])
{
check[q[i]] = true;
for (int j : res[q[i]])
{
int t = fw.get(n * 2 + k) - fw.get(max(a[j], b[j]) - 1);
if (a[j] <= b[j])
{
if (t & 1) ans += v[a[j] - 1];
else ans += v[b[j] - 1];
}
else
{
if (t & 1) ans += v[b[j] - 1];
else ans += v[a[j] - 1];
}
}
}
fw.update(q[i], 1);
}
for (int i : nopar)
{
int j = fw.get(n * 2 + k) - fw.get(max(a[i], b[i]) - 1);
if (j == 0)
{
ans += v[a[i] - 1];
continue;
}
if (j & 1) ans += v[b[i] - 1];
else ans += v[a[i] - 1];
}
cout << ans;
return 0;
}
