#include<fstream>

using namespace std;

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

long long Sume[500010];
long long N,K,A,B,Rest[100010]={1},Sol;

int main()
{
    fin>>N>>K>>A>>B;
    for(int i=1;i<=N;i++)
    {
        int x;
        fin>>x;
        Sume[i]=Sume[i-1]+x;
    }
    if(Sume[A]%K==0)
        Sol++;
    for(int i=A+1;i<=N;i++)
    {
        if(i>B)
            {
                Rest[Sume[i-B-1]%K]--;
            }
        Rest[Sume[i-A]%K]++;
        Sol+=Rest[Sume[i]%K];
    }
    fout<<Sol<<'\n';
}