// Source: https://usaco.guide/general/io

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

int main() {
	int n, k, m, c;
	cin >> n >> k >> m >> c;
	vector<int> a(c);
	for(int i = 0; i<c; i++){
		cin >> a[i];
	}
	int foglalt = 0;
	int elvihetocsapat = 0;
	vector<int> veg;
	int vk = 0;
	for(int i = 0; i<c; i++){
		if(vk < veg.size() && veg[vk]<a[i]){
			foglalt--;
			vk++;
		}
		if(n-foglalt>0){
			elvihetocsapat++;
			foglalt++;
			veg.push_back(a[i]+(m-1));
		}
	}
	cout << elvihetocsapat;
}