#include <bits/stdc++.h>
using namespace std;
int main() {
  unsigned long long n, m, k, l;
  cin >> n >> m >> k >> l;
  long long max_res = n / m;
  long long min_res = (l + k) / m + ((l + k) % m != 0);
  if ((k + l > n) || (max_res < min_res)) {
    cout << -1;
    return 0;
  }
  cout << min_res;
  return 0;
}
