#include <cstdio>

const int MAXN = 1e6;

int v[MAXN];

int main() {
  int n, k, d, i, j, ans;
  FILE *f = fopen("zombie.in", "r");
  fscanf(f, "%d%d%d", &d, &n, &k);
  for (int i = 0; i < n; ++i) {
    fscanf(f, "%d", &v[i]);
  }
  fclose(f);
  i = j = ans = 0;
  while (i < n) {
    while (j < n - 1 && v[j + 1] - v[i] <= d) {
      ++j;
    }
    if (j - i + 1 > k) {
      ans += k;
      i = j;
    } else {
      ++ans;
    }
    ++i;
  }
  f = fopen("zombie.out", "w");
  fprintf(f, "%d\n", ans);
  fclose(f);
  return 0;
}