#include<fstream>
#define NRME 500001 // numarul maxim de elemente
#define NRMR 100001 // numarul maxim de resturi

using namespace std;

FILE*in;
ofstream out("divk.out");

long int N;
long int K;
long int A, B;
long int X;
long long nr_subsecvente;
int nr[NRMR];
int S[NRME];

void read()
{
    in=fopen("divk.in", "r");

    fscanf(in, "%ld%ld%ld%ld", &N, &K, &A, &B);
    for (int i=1; i<=N; i++)
    {
        fscanf(in, "%ld", &X);

        S[i]=S[i-1]+X;
        S[i]%=K;

        if (i >= A)
            ++nr[S[i-A]];
        if (i > B)
            --nr[S[i-B-1]];

        nr_subsecvente+=nr[S[i]];
    }
}

void show()
{
    out<<nr_subsecvente;
}

int main()
{
    read();
    show();

    return 0;
}