#include <bits/stdc++.h>
using namespace std;
template <class T>
inline T bigmod(T p, T e, T M) {
  long long int ret = 1;
  for (; e > 0; e >>= 1) {
    if (e & 1) ret = (ret * p) % M;
    p = (p * p) % M;
  }
  return (T)ret;
}
template <class T>
inline T gcd(T a, T b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
template <class T>
inline T modinverse(T a, T M) {
  return bigmod(a, M - 2, M);
}
template <class T>
inline T bpow(T p, T e) {
  long long int ret = 1;
  for (; e > 0; e >>= 1) {
    if (e & 1) ret = (ret * p);
    p = (p * p);
  }
  return (T)ret;
}
int toInt(string s) {
  int sm;
  stringstream ss(s);
  ss >> sm;
  return sm;
}
int toLlint(string s) {
  long long int sm;
  stringstream ss(s);
  ss >> sm;
  return sm;
}
int ts, kk = 1;
int r, d, n;
int main() {
  int t, i, j, k;
  scanf("%d%d%d", &r, &d, &n);
  int m = r - d;
  int rs = 0;
  for (i = 0; i < n; i++) {
    scanf("%d%d%d", &j, &k, &t);
    if (j * j + k * k >= m * m + t * t + m * t * 2 &&
        j * j + k * k <= r * r + t * t - r * t * 2) {
      rs++;
    }
  }
  printf("%d\n", rs);
  return 0;
}
