#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long n, m, k;
  cin >> n >> m >> k;
  long long p[m], ans = 1, r = 1, nr = 0;
  for (long long i = 0; i < m; i++) cin >> p[i];
  long long ppg = (p[0] - 1) / k;
  while (r < m) {
    long long cpg = (p[r] - 1 - nr) / k;
    if (ppg != cpg) {
      nr = r;
      ppg = (p[r] - 1 - nr) / k;
      ans++;
    }
    r++;
  }
  cout << ans << endl;
}
