#include <bits/stdc++.h>
#include <limits.h>
#define i64 long long
#define fi first
#define se second
#define Endl endl
#define ed endl
#define ed endl
#define endl '\n'
#define dd double
#define de(x) cerr << #x << " " << x << endl;

using namespace std;

int n, k;
vector<pair<dd, dd>> p;
int check(dd w) {
  vector<dd> an;
  for (int i = 0; i < n; i++) {
    dd ss = p[i].se - w * p[i].fi;
    if (an.size() == 0 || an.back() <= ss) {
      an.push_back(ss);
    } else {
      an[upper_bound(an.begin(), an.end(), ss) - an.begin()] = ss;
    }
    if (an.size() >= k) {
      return 1;
    }
  }
  return 0;
}

int main() {
  cin >> n >> k;
  p.resize(n);
  for (int i = 0; i < n; i++) {
    cin >> p[i].fi >> p[i].se;
  }
  // sort(p.begin(), p.end(), cmp);
  dd l = -1e9, r = 1e9;
  // de(r - l)
  while ((r - l) > 0.000001) {
    dd mid = (r + l) / 2;
    // de(mid);
    if (check(mid)) {
      l = mid;
    } else {
      r = mid;
    }
  }
  // dd k = (l + r) / 2;
  cout << l << endl;

  return 0;
}