#include<stdio.h>

 #include<iostream>

 #include<algorithm>

 #include<math.h>

 #include<string.h>

 #include<string>

 #include<map>

 #include<set>

 #include<vector>

 #include<queue>

 #define M(a,b) memset(a,b,sizeof(a))

 using namespace std;

 typedef long long ll;

 int potato[];

 int main(){

     int n,h,k;

     scanf("%d%d%d",&n,&h,&k);

     for(int i=;i<n;i++)

         scanf("%d",&potato[i]);

     ll ans=,high=;

     for(int i=;i<n;i++){

         if(high+potato[i]<=h) high+=potato[i]; //能放下就放上去

         else{  //放不下就打完了再放

             high=potato[i];

             ans++;

         }

         ans+=high/k;

         high%=k;

     }

     if(high) ans++; //最后剩一点还要处理一下

     printf("%I64d\n",ans);

     return ;

 }

 /*

 5 6 3

 5 4 3 2 1

 5 6 3

 5 5 5 5 5

 5 6 3

 1 2 1 1 1

 */