#include <iostream>
#include <fstream>
using namespace std;

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

int n, k, a, b, x, s[500010], v[100010];
long long res;

void citire() {
    fin >> n >> k >>a >> b;
    for(int i = 1; i <= n; i++) {
        fin >> x;
        s[i] = (s[i-1]+x)%k;
    }
}

void solve() {
    for(int i = 1; i <= n; i++) {
        if(i > b)
            v[s[i-b]]--;
        if(i+1 > a)
            v[s[i-a+1]]++;
        res += v[s[i]];
    }
    fout << res;
}

int main() {
    citire();
    solve();

}