#include <fstream>
#include <vector>
using namespace std;
int n,k,a,b,x,v[500001],i,j,f[500001];
long long sol;
ifstream fin ("divk.in");
ofstream fout ("divk.out");

int main (){

    fin>>n>>k>>a>>b;
    for (i=1;i<=n;i++){
        fin>>x;
        v[i] = v[i-1] + x;
        v[i] %= k;

    }
    for (i=a;i<=n;i++){
        if (i>b)
            f[v[i-b-1]]--;

        f[v[i-a]]++;

        sol += f[v[i]];
    }
    fout<<sol;




    return 0;
}