#include <bits/stdc++.h>
using namespace std;
int main() {
  unsigned long long n, m, k, l, s, r, i, j, p;
  cin >> n >> m >> k >> l;
  p = k + l;
  if (p <= n) {
    r = (p + m - 1) / m;
    if (r * m <= n) {
      cout << r << endl;
      return 0;
    }
  }
  printf("-1\n");
  return 0;
}
