10 5 5
2 3 4 5 6
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1
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 1000000000000000000 2 1
1 1000000000000000000
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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
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1 1000000000 1000000000000 1000000000000000 1000000000000001
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1 2
 1000000000 2 1000000000
1 1000000000
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102306300054748096 267367244641009859
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 1000000000000000000 20 365
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2
 1
 10
 2
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 4
 1
 2
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 9
 2
 1
 4
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 2
 4
 35
 20

#include <bits/stdc++.h>
template <typename T>
class IntegerIterator {
 public:
  using value_type = T;
  using difference_type = std::ptrdiff_t;
  using pointer = T*;
  using reference = T;
  using iterator_category = std::input_iterator_tag;
  explicit IntegerIterator(T value) : value(value) {}
  IntegerIterator& operator++() {
    ++value;
    return *this;
  }
  IntegerIterator operator++(int) {
    IntegerIterator copy = *this;
    ++value;
    return copy;
  }
  IntegerIterator& operator--() {
    --value;
    return *this;
  }
  IntegerIterator operator--(int) {
    IntegerIterator copy = *this;
    --value;
    return copy;
  }
  T operator*() const { return value; }
  bool operator==(IntegerIterator rhs) const { return value == rhs.value; }
  bool operator!=(IntegerIterator rhs) const { return !(*this == rhs); }

 private:
  T value;
};
template <typename T>
class IntegerRange {
 public:
  IntegerRange(T begin, T end) : begin_(begin), end_(end) { ; }
  IntegerIterator<T> begin() const { return IntegerIterator<T>(begin_); }
  IntegerIterator<T> end() const { return IntegerIterator<T>(end_); }

 private:
  T begin_;
  T end_;
};
template <typename T>
class ReversedIntegerRange {
  using IteratorType = std::reverse_iterator<IntegerIterator<T>>;

 public:
  ReversedIntegerRange(T begin, T end) : begin_(begin), end_(end) { ; }
  IteratorType begin() const {
    return IteratorType(IntegerIterator<T>(begin_));
  }
  IteratorType end() const { return IteratorType(IntegerIterator<T>(end_)); }

 private:
  T begin_;
  T end_;
};
template <typename T>
IntegerRange<T> range(T to) {
  return IntegerRange<T>(0, to);
}
template <typename T>
IntegerRange<T> range(T from, T to) {
  return IntegerRange<T>(from, to);
}
template <typename T>
IntegerRange<T> inclusiveRange(T to) {
  return IntegerRange<T>(0, to + 1);
}
template <typename T>
IntegerRange<T> inclusiveRange(T from, T to) {
  return IntegerRange<T>(from, to + 1);
}
template <typename T>
ReversedIntegerRange<T> downrange(T from) {
  return ReversedIntegerRange<T>(from, 0);
}
template <typename T>
ReversedIntegerRange<T> downrange(T from, T to) {
  return ReversedIntegerRange<T>(from, to);
}
template <typename T>
ReversedIntegerRange<T> inclusiveDownrange(T from) {
  return ReversedIntegerRange<T>(from + 1, 0);
}
template <typename T>
ReversedIntegerRange<T> inclusiveDownrange(T from, T to) {
  return ReversedIntegerRange<T>(from + 1, to);
}
using namespace std;
class ATokitsukazeIVibrasivanieVeshei {
 public:
  static constexpr int kStressCount = 0;
  static void generateTest(std::ostream& test) {}
  void solve(std::istream& in, std::ostream& out) {
    int n, m;
    int64_t page;
    in >> n >> m >> page;
    vector<int64_t> poses(m);
    int64_t start = 0;
    int iter = 0;
    for (int i : range(m)) {
      int x;
      in >> x;
      --x;
      poses[i] = x;
    }
    int ans = 0;
    while (iter < m) {
      if (poses[iter] >= start + page) {
        start += (start - poses[iter]) / page * page;
        continue;
      }
      ++ans;
      int cntNow = 0;
      assert(poses[iter] < start + page);
      while (iter < m && poses[iter] < start + page) {
        ++iter;
        ++cntNow;
      }
      start += cntNow;
    }
    out << ans << "\n";
  }
};
int main() {
  std::ios_base::sync_with_stdio(false);
  ATokitsukazeIVibrasivanieVeshei solver;
  std::istream& in(std::cin);
  std::ostream& out(std::cout);
  in.tie(nullptr);
  out << std::fixed;
  out.precision(20);
  solver.solve(in, out);
  return 0;
}
