#include <bits/stdc++.h>
using namespace std;
ifstream fin("divk.in");
ofstream fout("divk.out");
int n,k,aa,b,i,x,rez,a[500001],dp[500001];
int main()
{
    fin>>n>>k>>aa>>b;
    for (i=1; i<=n; i++)
    {
        fin >>x;
        a[i]=a[i-1];
        a[i]+=x;
        a[i]%=k;
    }
    for (i=1; i<=n; i++)
    {
        if(i>=aa)
            dp[a[i-aa]]++;
        if(i>b)
            dp[a[i-b-1]]--;
        rez+=dp[a[i]];
    }

    fout<<rez<< '\n';
    return 0;
}