#include <cstdio>
#include <iostream>
#include <vector>
#include <queue>
#include <utility>
#include <algorithm>
#include <functional>
#include <string>
#include <cstring>
#include <cmath>
#include <map>
#include <set>
#include <bitset>
#include <stack>
#include <iomanip>
#define MOD 1000000007
#define NMAX 500005
#define INF 0x3f3f3f3f

using namespace std;

FILE *fin = freopen("divk.in", "r", stdin);
FILE *fout = freopen("divk.out", "w", stdout);

typedef pair<int, int> pii;

int sp[NMAX], fr[NMAX];

int main() {
	int n, a, b, k, i;
	long long sum = 0;

	scanf("%d%d%d%d", &n, &k, &a, &b);

	for (i = 1; i <= n; ++i) {
		scanf("%d", &sp[i]);

		sp[i] = (sp[i] + sp[i - 1]) % k;

		if (i >= a)
			++fr[sp[i - a]];
		if (i > b)
			--fr[sp[i - b - 1]];

		sum += 1LL*fr[sp[i]];
	}

	cout << sum;

	return 0;
}