#include <iostream>
#include <fstream>

using namespace std;

ifstream fin("divk.in");
ofstream fout("divk.out");

int N,K,A,B,V[500005],S[500005],R[100005],nr;

int main()
{
  fin>>N>>K>>A>>B;

  for(int i=1;i<=N;i++)
  {
    fin>>V[i];
    S[i]=(S[i-1]+V[i])%K;
  }

  for(int i=A;i<=N;i++)
  {
        R[S[i-A]]++;
        if(i>B)
        R[S[i-B-1]]--;
        nr=nr+R[S[i]];
  }

   fout<<nr;
  return 0;
}