#include <bits/stdc++.h>
using namespace std;
long long MOD = 998244353;
string alpha_upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string alpha_lower = "abcdefghijklmnopqrstuvwxyz";
double eps = 1e-12;
template <class T>
void print_array(T v[], long long size) {
  for (int i = 0; i < size; i++) {
    cout << v[i] << " ";
  }
  cout << "\n";
}
template <class T1>
void print_vector(vector<T1> v, long long size) {
  for (int i = 0; i < size; i++) {
    cout << v[i] << " ";
  }
  cout << "\n";
}
template <class Tm1, class Tm2>
void print_map(map<Tm1, Tm2> m) {
  for (auto it = m.begin(); it != m.end(); it++) {
    cout << (*it).first << " : " << (*it).second << "\n";
  }
}
void solve() {
  long long n, m, k, count = 0, prev = 0;
  cin >> n >> m >> k;
  vector<long long> p(m);
  for (long long i = 0; i < m; i += 1) {
    cin >> p[i];
  }
  long long i = 0, mi = 0, x;
  while (i < m) {
    x = 0;
    prev = ceil((long double)(p[i] - mi) / k);
    while ((ceil((long double)(p[i] - mi) / k) <= prev) && (i < m)) {
      i++;
      x++;
    }
    mi += x;
    count++;
  }
  cout << count << "\n";
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  solve();
  return 0;
}
