#include <bits/stdc++.h>
int x[100010];
int main() {
  int a, b, c, i;
  scanf("%d%d%d", &a, &b, &c);
  for (i = 1; i <= a; i++) scanf("%d", &x[i]);
  int s = 0, t = 1;
  long long int count = 0;
  while (1) {
    if (t > a && s == 0) {
      printf("%I64d", count);
      return 0;
    }
    while (t <= a && s + x[t] <= b) s += x[t], t++;
    if (s < c) {
      count++;
      s = 0;
    } else {
      count += (s / c);
      s = s % c;
    }
  }
}
