#include <bits/stdc++.h>
using namespace std;
long long powmod(long long a, long long b) {
  long long res = 1;
  a %= 1000000007;
  for (; b; b >>= 1) {
    if (b & 1) res = res * a % 1000000007;
    a = a * a % 1000000007;
  }
  return res;
}
int gcd(int x, int y) {
  while (y) {
    int t = x % y;
    x = y;
    y = t;
  }
  return x;
}
template <typename T>
inline bool chkmin(T &a, const T &b) {
  return a > b ? a = b, 1 : 0;
}
template <typename T>
inline bool chkmax(T &a, const T &b) {
  return a < b ? a = b, 1 : 0;
}
namespace FastIO {
bool IOError = 0;
inline char NextChar() {
  static char buf[100000], *p1 = buf + 100000, *pend = buf + 100000;
  if (p1 == pend) {
    p1 = buf;
    pend = buf + fread(buf, 1, 100000, stdin);
    if (pend == p1) {
      IOError = 1;
      return -1;
    }
  }
  return *p1++;
}
inline bool Blank(char c) {
  return c == ' ' || c == '\n' || c == '\r' || c == '\t';
}
inline void read(int &x) {
  bool sign = 0;
  char ch = NextChar();
  x = 0;
  for (; Blank(ch); ch = NextChar())
    ;
  if (IOError) return;
  if (ch == '-') sign = 1, ch = NextChar();
  for (; ch >= '0' && ch <= '9'; ch = NextChar()) x = x * 10 + ch - '0';
  if (sign) x = -x;
}
inline void read(long long &x) {
  bool sign = 0;
  char ch = NextChar();
  x = 0;
  for (; Blank(ch); ch = NextChar())
    ;
  if (IOError) return;
  if (ch == '-') sign = 1, ch = NextChar();
  for (; ch >= '0' && ch <= '9'; ch = NextChar()) x = x * 10 + ch - '0';
  if (sign) x = -x;
}
inline void read(double &x) {
  bool sign = 0;
  char ch = NextChar();
  x = 0;
  for (; Blank(ch); ch = NextChar())
    ;
  if (IOError) return;
  if (ch == '-') sign = 1, ch = NextChar();
  for (; ch >= '0' && ch <= '9'; ch = NextChar()) x = x * 10 + ch - '0';
  if (ch == '.') {
    double tmp = 1;
    ch = NextChar();
    for (; ch >= '0' && ch <= '9'; ch = NextChar())
      tmp /= 10.0, x += tmp * (ch - '0');
  }
  if (sign) x = -x;
}
inline void read(char *s) {
  char ch = NextChar();
  for (; Blank(ch); ch = NextChar())
    ;
  if (IOError) return;
  for (; !Blank(ch) && !IOError; ch = NextChar()) *s++ = ch;
  *s = 0;
}
inline void read(char &c) {
  for (c = NextChar(); Blank(c); c = NextChar())
    ;
  if (IOError) {
    c = -1;
    return;
  }
}
}  // namespace FastIO
using namespace FastIO;
const long long INF = 1000000000000000000LL;
long long t[601000];
int main() {
  long long n, a;
  int m;
  long long d, now;
  read(n), read(m), read(a), read(d);
  now = 0;
  for (int i = 1; i <= m; i++) {
    read(t[i]);
  }
  int i = 1;
  long long num = d / a + 1, ans = 0;
  for (int i = 1; i <= m; i++) {
    if (t[i] <= now) continue;
    long long x = min(t[i] / a, n), y = min(now / a, n);
    long long kk = x - y;
    ans += (kk + num - 1) / num;
    if (kk != 0) {
      now = (x + 1) * a + d;
      if (kk % num)
        now -= (kk % num) * a;
      else
        now -= num * a;
    }
    if (now < t[i]) now = t[i] + d, ans++;
  }
  if (now < n * a) ans += (n - now / a + num - 1) / num;
  cout << ans << endl;
  return 0;
}
