10 5 5
2 3 4 5 6
 1 1 1
1
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 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
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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
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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
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2
 1
 10
 2
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 1
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 1
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 2
 4
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 20

#include <bits/stdc++.h>
using namespace std;
double pi = acos(-1);
inline long long lowbit(long long x) { return x & (-x); }
inline long long min(long long a, long long b) { return a < b ? a : b; }
inline long long max(long long a, long long b) { return a > b ? a : b; }
const double Rad_to_deg = 45.0 / atan(1.0);
inline long long floor(const long long& a, const long long& b) { return a / b; }
inline long long gcd(long long a, long long b) {
  return b == 0 ? a : gcd(b, a % b);
}
const long long INF = 4223372036854775807, max_n = 1000010, mod = 998244353;
inline int cal(int x) {
  int res = 0;
  while (x) {
    x /= 10;
    res++;
  }
  return res;
}
inline long long ceil(const long long& a, const long long& b) {
  if (a % b == 0) return a / b;
  return a / b + 1;
};
inline long long pow(long long a, long long b, long long mod) {
  long long res = 1;
  a %= mod;
  assert(b >= 0);
  for (; b; b >>= 1) {
    if (b & 1) res = res * a % mod;
    a = a * a % mod;
  }
  return res;
}
inline int mul(int a, int b) { return (long long)a * b % mod; }
long long n, m, k;
long long jihe;
long long ans;
long long a[max_n];
long long f(long long x, int i) { return (x + k - i) / k; }
int main() {
  cin >> n >> m >> k;
  jihe = 0;
  for (int i = 1; i <= m; i++) {
    cin >> a[i];
  }
  for (int i = 1; i <= m; i++) {
    long long dang = f(a[i], i);
    if (jihe == dang) {
    } else {
      ans++;
      jihe = dang;
      for (int j = i + 1; j <= m; j++) {
        long long dang = f(a[j], i);
        if (jihe == dang) {
          i++;
        } else {
          jihe = 0;
          break;
        }
      }
    }
  }
  cout << ans;
}
