#include <fstream>

using namespace std;

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

const int NMax = 500000;

int V[NMax + 5], R[NMax + 5], A, B, N, K, sol;

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

    for(int i = 1; i <= N; i++) {///i-B-1   i-B.....i-A+1   i
        fin >> V[i];

        V[i] = (V[i - 1] + V[i] % K) % K;

        if(i - A >= 0) ///cond existenta
            R[V[i - A]]++;

        if(i - B - 1 >= 0)
            R[V[i - B - 1]]--;

        sol += R[V[i]];
    }
    fout << sol << '\n';

    fin.close();
    fout.close();

    return 0;
}