#include <fstream>
using namespace std;

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

int v[500001],fv[100001],i,n,A,B,k,x;
long long int rasp;
int main()
{
    f>>n>>k>>A>>B;
    for (i=1;i<=n;++i)
        {
            f>>x;
            v[i]=(v[i-1]+x)%k;
        }
    for(i=A;i<=n;++i)
        {
            ++fv[v[i-A]];
            if (i>B)--fv[v[i-B-1]];
            rasp+=fv[v[i]];
        }
    g<<rasp;











    return 0;
}