#include <bits/stdc++.h>
using namespace std;
long long n, m, k;
long long a[100050];
int main() {
  scanf("%lld%lld%lld", &n, &m, &k);
  for (int i = 1; i <= m; i++) scanf("%lld", &a[i]);
  long long ans = 0, j = 0, term = (a[1] - j - 1) / k;
  for (int i = 2; i <= m; i++)
    if ((a[i] - j - 1) / k != term) ans++, j = i - 1, term = (a[i] - j - 1) / k;
  printf("%lld\n", ans + 1);
  return 0;
}
