#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("divk.in");
ofstream fout("divk.out");

int a[500100];
int fr[100100];

int main()
{
    int n, k, A, i, B, x, s=0;
    fin>>n>>k>>A>>B;
    for(i=1;i<=n;i++)
    {
        fin>>x;
        a[i]=(x+a[i-1])%k;
        //cout<<a[i]<<" ";
    }
   // cout<<"\n";
    for(i=1;i<=n;i++)
    {
        if(i>=A+1)
        {
            fr[a[i-A]]++;
        }
        if(i>=B+1)
        {
            fr[a[i-B]]--;
        }
       // cout<<fr[a[i]]<<" ";
        s+=1LL*(fr[a[i]]*(fr[a[i]]+1)/2);
    }
    //cout<<"\n";
    fout<<s;
}