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