#include <fstream>

using namespace std;

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

#define N 500005
#define K 100005

int n, k, a, b;
int nr[K];
int r[N];
int rez;

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

    for(int i = 1 ; i <= n; i++)
    {
        in >> r[i];
        r[i] = (r[i - 1] + r[i]) % k;
        if(i >= a) nr[r[i - a]]++;
        if(i > b) nr[r[i - b - 1]]--;
        rez += nr[r[i]];
    }

    out << rez << '\n';
    return 0;
}