#include <bits/stdc++.h>
using namespace std;
long long n, m, k;
long long a[100005];
void Init() {
  cin >> n >> m >> k;
  for (long long i = 1; i <= m; i++) cin >> a[i];
}
long long res = 0;
void solve() {
  long long page = (a[1] - 1) / k;
  long long luu = 0;
  long long count_1 = 0;
  bool ok = true;
  for (long long i = 1; i <= m; i++) {
    count_1++;
    if ((a[i] - 1 - luu) / k > page) {
      res++;
      luu = count_1 - 1;
      page = (a[i] - 1 - luu) / k;
      if (i == n) ok = false;
    }
  }
  cout << res + 1;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  Init();
  solve();
  return 0;
}
