#include<fstream>
#define NMax 500005
using namespace std;
ifstream fin("divk.in");
ofstream fout("divk.out");

int N,K,A,B,Sol;
int S[NMax],R[NMax/5];

int main()
{
    fin>>N>>K>>A>>B;

    for(int i=1;i<=N;++i)
    {
        int x; fin>>x;  x%=K;
        S[i]=(S[i-1]+x)%K;
        if(i>=A)    R[S[i-A]]++;
        if(i>B) R[i-B-1]--;

        Sol+=R[S[i]];
    }
    fout<<Sol<<"\n";

    fin.close();
    fout.close();
    return 0;
}