#include<bits/stdc++.h>

using namespace std;

long long n,m,d,l,s[100010];

long long tot=1,f,i=1,ans;

inline long long read(){

    long long ret=0,f=1;char ch=getchar();

    while (ch<'0'||ch>'9') {if (ch=='-') f=-f;ch=getchar();}

    while (ch>='0'&&ch<='9') ret=ret*10+ch-'0',ch=getchar();

    return ret*f;

}

inline void write(long long x){

    if(x<0){putchar('-'),write(-x);return;}

    if(x/10)write(x/10);putchar(x%10+'0');

}

int main(){

    freopen("cowcar.in","r",stdin);

    freopen("cowcar.out","w",stdout);

    cin>>n>>m>>d>>l;

    for(int ss=1;ss<=n;ss++)s[ss]=read();

    sort(s+1,s+n+1);

    while(i<=n){

        if(s[i]-f*d<l){          //Bye Bye

              i++;continue;

        }

        if(n-i+1<=m){            //Let it in

             ans+=n-i+1;break;

        }

        ans+=m,i+=m,f++;

    }

    write(ans);

    return 0;

}