#include <bits/stdc++.h>
#define rep(i,a,b) for(int i=(a);i<=(b);++i)

using namespace std;

const int N = 2e5 + 10;
int x[N], y[N], rnk[N], f[N], n, k;
double g[N], tg[N];
int c[N];
inline int add(int x, int y) {
  for(; x <= n; x += x & (-x)) c[x] = max(c[x], y);
}
inline int qry(int x) {
  int val = 0;
  for(; x; x -= x & (-x)) val = max(val, c[x]);
  return val;
}
inline bool check(double k0) {
  rep(i,1,n) tg[i] = g[i] = y[i] - k0 * x[i];
  sort(tg + 1, tg + n + 1);
  int tn = unique(tg + 1, tg + n + 1) - tg - 1;
  rep(i,1,n) rnk[i] = lower_bound(tg + 1, tg + tn + 1, g[i]) - tg;
  // cout << k0 << ',' << tn << endl;
  // rep(i,1,n) cout << g[i] << ' ';
  // cout << endl;
  // rep(i,1,n) cout << rnk[i] << ' ';
  // cout << endl;
  rep(i,1,n) c[i] = 0;
  int ans = 0;
  rep(i,1,n) {
    ans = max(ans, f[i] = qry(rnk[i]) + 1);
    add(rnk[i], f[i]);
  }
  // cout << "ans = " << ans << endl;
  return ans >= k;
}

signed main() {
  // ios::sync_with_stdio(false);
  // cin.tie(NULL);
  // cin >> n >> k;
  scanf("%d %d", &n, &k);
  rep(i,1,n) scanf("%d %d", x + i, y + i);
  double L = -1e9, R = 1e9;
  for(int cnt = 1; cnt <= 100; ++ cnt) {
    double mid = (L + R) / 2;
    if(check(mid)) L = mid;
    else R = mid;
  }
  printf("%.10f\n", L);
  return 0;
}