#include <fstream>
using namespace std;

ifstream is ("divk.in");
ofstream os ("divk.out");

int N, A, B, K;
int v[500003], r[100003];
int S;

int main()
{
    is >> N >> K >> A >> B;
    for (int i = 1, x; i <= N; ++i)
        is >> x, v[i] = (v[i-1] + x) % K;
    for (int i = 0; i <= N; ++i)
    {
        if (i >= A)
            r[v[i-A]]++;
        if (i-1 >= B)
            r[v[i-B-1]]--;
        S += r[v[i]];
    }
    os << S;
    is.close();
    os.close();
}