#include <bits/stdc++.h>
using namespace std;
const int N = 1000;
const double eps = 1e-9;
long long INF = 1e9;
const int OO = 0x3f3f3f3f;
int dx[] = {1, -1, 0, 0, 1, -1, 1, -1};
int dy[] = {0, 0, 1, -1, 1, -1, -1, 1};
bool comp(pair<int, int> a, pair<int, int> b) {
  if (a.first < b.first)
    return true;
  else if (a.first > b.first)
    return false;
  else
    return a.first < b.first;
}
void read(string str, int node) {
  stringstream ss;
  int number;
  ss << str;
  while (ss >> number) cout << number << endl;
}
long long fp(long long b, long long p) {
  if (p == 0) return 1;
  if (p % 2 == 0) return fp((b * b) % INF, p / 2);
  return (fp(b, p - 1) * b) % INF;
}
unsigned long long read_binary(string s) {
  unsigned long long x = 0, tmp = 1;
  for (int i = s.size() - 1; i >= 0; i--) {
    x = (x + tmp * (s[i] - '0')) % INF;
    tmp = (tmp * 2) % INF;
  }
  return x;
}
long long com(long long x, long long y) {
  long long sum = 1;
  for (int i = 1; i <= y; i++) {
    sum *= x;
    x--;
    sum /= i;
  }
  return sum;
}
long long gcd(long long n1, long long n2) {
  if (n2 != 0)
    return gcd(n2, n1 % n2);
  else
    return n1;
}
int setBit(int num, int idx, int val = 1) {
  return (val) ? (num | (1 << idx)) : (num & ~(1 << idx));
}
int getBit(int num, int idx) { return ((num >> idx) & 1) == 1; }
int cntBit(int num) {
  int ret = 0;
  while (num) {
    if (num % 2) ret++;
    num /= 2;
  }
  return ret;
}
bool sum[1500];
void sieve() {
  sum[0] = sum[1] = 1;
  for (int i = 2; i * i < 1002; i++) {
    if (!sum[i]) {
      for (int j = 2 * i; j < 1002; j += i) {
        sum[j] = 1;
      }
    }
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  ;
  long long n, h, k;
  cin >> n >> h >> k;
  vector<long long> a(n);
  for (int i = 0; i < n; i++) cin >> a[i];
  reverse(a.begin(), a.end());
  long long cnt = 0;
  long long cur = 0;
  while (!a.empty()) {
    while (1) {
      if (a.empty()) break;
      if ((cur + a.back()) <= h) {
        cur += a.back();
        a.pop_back();
      } else if ((cur + a.back()) > h)
        break;
    }
    cnt += ((cur / k));
    if ((cur / k) == 0) cnt++;
    if ((cur / k) == 0) {
      if ((cur - k) <= 0)
        cur = 0;
      else
        cur -= k;
    } else
      cur -= ((cur / k) * (k));
  }
  if (cur > 0) {
    double cc = cur, kk = k;
    cnt += ceil(cc / kk);
  }
  cout << cnt << endl;
}
