#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 : v) cin >> i;
    vector<int> sz(1+n, 0);
    if(k < m) {
        cout << "0\n";
        return 0;
    }
    int vind = 0;
    int db = 0;
    for(int i = 1; i <= k; ++i) {
        while(vind < c) {
            if(v[vind] == i) {
                for(int j = 1; j <= n; ++j) {
                    if(sz[j] <= i) {
                        sz[j] = i + m;
                        ++db;
                        break;
                    }
                }
                ++vind;
            } else break;
        }
    }
    cout << db << "\n";
    return 0;
}