#include <bits/stdc++.h>
using namespace std;
int main() {
  int x, t, t2, n;
  cin >> x >> t >> t2;
  long long c = 0;
  vector<int> B(t), F(t), I(t);
  for (int i = 0; i < t; i++) cin >> B[i] >> F[i] >> I[i];
  while (t2--) {
    cin >> n;
    for (int i = 0; i < t; i++)
      if (n >= B[i] && n <= F[i]) c += I[i] - B[i] + n;
  }
  cout << c;
}
