#include <fstream>
using namespace std;

ifstream cin ("divk.in");
ofstream cout ("divk.out");

int n, k, a, b, dp[500010], rest[100010], i;
long long ans;

int main() {
    cin >> n >> k >> a >> b;
    for (i=1; i<=n; i++) {
        cin >> dp[i];
        dp[i] = (dp[i] + dp[i-1])%k;
        if (i >= a)
          rest[dp[i - a]]++;
        if (i - b >= 1)
          rest[dp[i - b - 1]]--;
        ans += rest[dp[i]];
    }
    cout << ans;
    return 0;
}