#include <bits/stdc++.h>
using namespace std;

int main() {
	int n, k, m, c;
	cin >> n >> k >> m >> c;
	vector<int> v(c);
	for (int i = 0; i < c; ++i) {
		cin >> v[i];
	}

	sort(v.begin(), v.end());

	queue<int> q;
	int curr_free = n;
	int ans = 0;

	for (int i = 0; i < c; ++i) {
		while (!q.empty() && q.front() < v[i]) {
			++curr_free;
			q.pop();
		}

		if (curr_free) {
			q.push(v[i] + m);
			++ans;
			--curr_free;
		}
	}

	cout << ans << endl;
}