#include <fstream>
using namespace std;
ifstream f("divk.in");
ofstream g("divk.out");

int x, n, k, a, b, i, j;
int s[500001];
long long sol, nr1[500001], nr2[500001];

int main() {
    f >> n >> k >> a >> b;
    for (i = 1; i <= n; i++) {
        f >> x;
        s[i] = (s[i-1]+x)%k;
        if (i >= a)
            nr1[s[i-a]]++;
        if (i > b)
            nr2[s[i-b-1]]++;
        sol += nr1[s[i]] - nr2[s[i]];
    }
    g << sol;
    return 0;
}