#include <fstream>

using namespace std;
ifstream fin("divk.in");
ofstream fout("divk.out");
int a,b,i,s[500005],inc,sfar,nrh,suma,n,k,x,j,sum,vf[500005],nr;
int main()
{
    fin>>n>>k>>a>>b;
    for (i=1; i<=n; i++)
    {
        fin>>x;
        s[i]=(s[i-1]+x)%k;
    }
    sum=0;
    if (b<a) swap(a,b);
    for (j=1;j<=n;j++)
    {
        if (j>=a)
        {
           vf[s[j-a]]++;
        }
        nr+=vf[s[j]];
        if (j>=b) vf[s[j-b]]--;
    }
    fout<<nr;


    return 0;
}