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