#include <fstream>

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

int N, K, A, B;
int f[100007];
int v[500007];
int suma = 0;
int main()
{
    int i, sol = 0;

    fin >> N >> K >> A >> B;

    for( i = 1;  i <= N; i++)
       {
           fin >> v[i];
           suma += v[i];
           suma %= K;
           v[i] = suma;
       }
    int pun = 1, scot = 0;
    for( i = A; i <= N; i++)
    {
         if(i - scot > B)
        {
            scot++;
            f[v[scot]]--;
        }
        f[ v[ pun++]]++;
        sol += f[ v[ i]];
    }
    fout<<sol;
    return 0;
}