#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, m, k, l;
  cin >> n >> m >> k >> l;
  if (n / m and (m * (n / m)) - k >= l) {
    long long res, lo = 1, hi = n / m;
    while (lo <= hi) {
      long long mid = (hi + lo) / 2;
      if (mid * m >= l + k) {
        res = mid;
        hi = mid - 1;
      } else
        lo = mid + 1;
    }
    cout << res << endl;
  } else
    cout << "-1" << endl;
  return 0;
}
