#include <fstream>
#define ValN 500005

using namespace std;

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

int K, N, A, B;
int i, v[ValN];
int x[ValN];
long long nr;

int main()
{
    fin >> N >> K >> A >> B;
    for (i=1; i<=N; i++)
    {
        fin >> v[i];
        v[i]+=v[i-1];
        v[i]%=K;
    }
    for (i=A; i<=N; i++)
    {
        x[v[i-A]]++;
        nr+=x[v[i]];
        if (i>=B)
          x[v[i-B]]--;
    }
    fout << nr;
    fin.close();
    fout.close();
    return 0;
}