#include <bits/stdc++.h>
using namespace std;
template <typename T>
void out(T x) {
  cout << x << endl;
  exit(0);
}
const int maxn = 1e6 + 7;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long num, friends, have, minneed;
  cin >> num >> friends >> have >> minneed;
  if (minneed > (num - have)) out(-1);
  long long each = (have + minneed + friends - 1) / friends;
  if (each * friends > num) out(-1);
  out(each);
  return 0;
}
