#include <bits/stdc++.h>

#define MAXK 100005
#define MAXN 500005

int N, K, A, B;
int Rest[MAXK];
int SP[MAXN];

std::ifstream In ("divk.in");
std::ofstream Out("divk.out");

void Citire() {
    In >> N >> K >> A >> B;
}

void Rezolvare() {
    int Sum = 0, Ans = 0;

    for (int i=1, X; i<=N; ++i) {
        In >> X;
        SP[i] = (SP[i-1] + X) % K;
        if (i>=A)
            Rest[SP[i-A]]++;
        if (i>=B+1)
            Rest[SP[i-B-1]]--;
        Ans += Rest[SP[i]];
    }   Out << Ans << '\n';
}

int main()
{
    Citire();
    Rezolvare();

    return 0;
}