#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll INF = 2e18;
int main() {
  for (int _ = (0); _ < (1); _++) {
    ios_base::sync_with_stdio(0);
    ll n, m, d, a;
    cin >> n >> m >> a >> d;
    vector<ll> ts(m);
    for (int i = (0); i < (m); i++) cin >> ts[i];
    ts.push_back(INF);
    ++m;
    ll re = 1;
    ll cur = min(a, ts[0]);
    ll one = d / a + 1;
    while (1) {
      auto it = lower_bound(ts.begin(), ts.end(), cur + d + 1);
      if (it == ts.end()) {
        if (cur + d >= n * a) break;
        ll nxt = (cur + d) / a * a + a;
        assert(nxt <= n * a);
        ll t = a * n - nxt;
        re += ((t + one - 1) / a + one - 1) / one;
        break;
      }
      ll x = *it;
      ll y = min(n * a + 1, (cur + d) / a * a + a);
      if (y == n * a + 1) y = x;
      if (cur % a == 0 && y <= x) {
        ll px = min(n, x / a) * a;
        if (px >= cur) {
          ll ad = (px - cur) / a / one;
          re += ad;
          cur += ad * one * a;
        }
      }
      it = lower_bound(ts.begin(), ts.end(), cur + d + 1);
      if (it == ts.end()) break;
      x = *it;
      y = min(n * a + 1, (cur + d) / a * a + a);
      if (y == n * a + 1) y = x;
      cur = min(x, y);
      ++re;
    }
    cout << re - 1 << endl;
  }
  return 0;
}
