#include <algorithm>
using namespace std;

#define DIM 500005

int s[DIM],v[DIM];
int n,k,a,b,nrt;

void read ()
{
    int i,nr;

    scanf ("%d%d%d%d",&n,&k,&a,&b);
    for (i=1; i<=n; ++i)
    {
        scanf ("%d",&nr);
        s[i]=(s[i-1]+nr)%k;
    }
}

void solve ()
{
    int i;

    for (i=1; i<=n; ++i)
    {
        nrt+=v[s[i]];
        if (i>b-1)
            --v[s[i-b+1]];
        if (i>a-2)
            ++v[s[i-a+2]];
    }
    printf ("%d",nrt);
}

int main ()
{
    freopen ("divk.in","r",stdin);
    freopen ("divk.out","w",stdout);

    read ();
    solve ();

    return 0;
}