#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, m, l, k;
  cin >> n >> m >> k >> l;
  long long count;
  if ((k + l) % m == 0)
    count = (k + l) / m;
  else
    count = (k + l) / m + 1;
  if (count * m > n)
    cout << "-1";
  else
    cout << count;
  return 0;
}
