#include <iostream>
#include <bits/stdc++.h>
using ll = long long;
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];
    }
    vector<int> idevez(n, 0);
    ll ans = 0;
    for (int i = 0; i < c; i++){
        for (int j = 0; j < n; j++){
            if (idevez[j] < v[i]){
                ans++;
//                cout << v[i] << " " << j << "\n";
                idevez[j] = v[i]+m-1;
                break;
            }
        }
    }
//    for (int i = 0; i < n; i++){
//        cout << idevez[i] << " ";
//    }
    cout << ans;
    return 0;
}