10 5 5
2 3 4 5 6
 1 1 1
1
 1000000000000000000 10 68
9818112234872670 233245257111863071 266483628625876079 375103213040049805 431982380866113633 489732004669478331 501030096787260719 541800997319766183 551892546260532408 696178619227890200
 1000000000000000000 2 1
1 1000000000000000000
 33 32 1
1 2 3 4 5 6 7 8 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
 101 55 10
1 3 5 7 8 9 10 16 18 21 22 23 24 25 27 30 32 35 36 37 38 39 40 43 45 47 49 50 51 52 54 57 59 61 64 66 67 68 69 70 71 72 73 80 83 86 87 88 89 90 91 92 96 97 98
 1000000000000000000 5 1000
1 1000000000 1000000000000 1000000000000000 1000000000000001
 15 15 15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
 21 21 20
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
 45 43 2
1 2 3 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
 107 20 13
5 9 20 25 26 30 37 45 51 58 62 73 82 87 89 90 99 101 104 106
 3 2 1
1 2
 1000000000 2 1000000000
1 1000000000
 11 7 3
2 3 4 5 6 7 11
 13 9 4
1 2 3 6 7 8 11 12 13
 1000000000000000000 2 1000000000
102306300054748096 267367244641009859
 16 7 5
2 3 4 5 6 15 16
 35 35 1
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
 1000000000000000000 20 365
31881893160049984 103938857870698567 103962228223609431 140762820261865064 175962215264653912 239086305245565642 354522451098745823 383839975876242372 443471287955807705 478923027151493682 511195154588214957 619570919279066139 677571312513476877 705864797651447277 789633853044745934 867300890280086078 883297431113041450 891736036124527038 937306858250803630 990892290394455512

2
 1
 10
 2
 32
 15
 4
 1
 2
 35
 9
 2
 1
 4
 4
 2
 4
 35
 20

#include <bits/stdc++.h>
using namespace std;
const long long dx[4] = {-1, 1, 0, 0};
const long long dy[4] = {0, 0, -1, 1};
long long XX[] = {-1, -1, -1, 0, 0, 1, 1, 1};
long long YY[] = {-1, 0, 1, -1, 1, -1, 0, 1};
const long long N = (long long)(6 * 1e5 + 10);
const long long M = 1e9 + 7;
long long fact[N], invfact[N];
long long pow(long long a, long long b, long long m) {
  long long ans = 1;
  while (b) {
    if (b & 1) ans = (ans * a) % m;
    b /= 2;
    a = (a * a) % m;
  }
  return ans;
}
long long modinv(long long k) {
  return pow(k, (long long)998244353 - 2, (long long)998244353);
}
void precompute() {
  fact[0] = fact[1] = 1;
  for (long long i = 2; i < N; i++)
    fact[i] = fact[i - 1] * i, fact[i] %= (long long)998244353;
  invfact[N - 1] = modinv(fact[N - 1]);
  for (long long i = N - 2; i >= 0; i--)
    invfact[i] = invfact[i + 1] * (i + 1), invfact[i] %= (long long)998244353;
}
long long nCr(long long x, long long y) {
  if (y > x) return 0;
  long long num = fact[x];
  num *= invfact[y];
  num %= (long long)998244353;
  num *= invfact[x - y];
  num %= (long long)998244353;
  return num;
}
pair<long long, long long> find(long long del, long long n, long long m,
                                long long k, long long temp, long long a,
                                long long b) {
  if (del <= b) return {a, b};
  long long a1 = b + 1, b1 = a1 + k - 1;
  long long n1 = ((del - a1) / k);
  long long x = a1 + (n1 * k), y = b1 + (n1 * k);
  return {x, y};
}
int32_t main() {
  ;
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  long long n, m, k;
  cin >> n >> m >> k;
  vector<long long> p(m, 0);
  for (long long i = 0; i < m; i++) cin >> p[i];
  long long a = 0, b = 0, cnt = 0;
  long long i = 0;
  long long temp = 0, local = 0;
  long long x = 0;
  while (i < m) {
    long long del = p[i];
    if (del >= a and del <= b) {
      if (del == a) a++;
      local++;
      temp++, i++;
    } else {
      b += local;
      pair<long long, long long> p = find(del, n, m, k, temp, a, b);
      a = p.first;
      b = p.second;
      cnt++, local = 0;
    }
  }
  cout << cnt << endl;
}
