#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, m, k, l;
  scanf("%lld %lld %lld %lld", &n, &m, &k, &l);
  long long x = (k + l + m - 1) / m;
  printf("%lld\n", (m * x <= n) ? x : -1);
  return 0;
}
