#include <fstream>

using namespace std;

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

int v[500005], nou[100005];

int main()
{
    int n, a, b, k;
    in >> n >> k >> a >> b;

    int temp;
    for (int i = 1; i <= n; i++) {
        in >> temp;
        v[i] = (v[i-1] + temp) % k;
    }
    long long sol = 0;
    for (int i = a; i <= n; i++) {
        nou[v[i - a]] ++;
        sol += nou[v[i]];
        if (i >= b) {
            nou[v[i - b]] --;
        }
    }
    out << sol << "\n";

    return 0;
}