#include <bits/stdc++.h>
using namespace std;
int read() {
  char c = getchar();
  int d = 0, f = 1;
  for (; c < '0' || c > '9'; c = getchar())
    if (c == '-') f = -1;
  for (; c >= '0' && c <= '9'; d = d * 10 + c - 48, c = getchar())
    ;
  return d * f;
}
int r, d, n;
const int N = 100001;
struct xint {
  int x, y, r;
} a[N];
int main() {
  r = read(), d = read(), n = read();
  int ans = 0;
  for (int i = 1; i <= n; ++i) {
    a[i].x = read(), a[i].y = read(), a[i].r = read();
    int dis = a[i].x * a[i].x + a[i].y * a[i].y;
    if (dis >= (r - d + a[i].r) * (r - d + a[i].r) && r >= a[i].r &&
        dis <= (r - a[i].r) * (r - a[i].r))
      ans++;
  }
  cout << ans << endl;
}
