//#pragma GCC optimize(3)
#include <bits/stdc++.h>

#define f(i, n, m) for (long long i = n; i <= m; ++i)
#define unf(i, n, m) for (long long i = n; i >= m; --i)
#define kong NULL
#define debug cout << "sss" << endl;

using ll = long long;
using ull = unsigned long long;
using point_t = double; // 计算几何的默认类型

const double e = exp(1.0);
const double pi = acos(-1.0);
constexpr ll inf = 0x3f3f3f3f3f3f3f3f;
constexpr ll maxx = 0x3f3f3f3f3f3f3f3f;
constexpr ll minn = 0xc0c0c0c0c0c0c0c0;

// #define endl '\n'
constexpr char blank = ' ';
constexpr ll mod = (ll)998244353;
constexpr size_t N = (size_t)1e6 + 6;

#ifdef _DEBUG
#define Crash(...) (__debugbreak(), 0)
#define Debug(...) (__debugbreak(), 0)
#else
#define Crash(...) (exit(-1), 0)
#define Debug(...) ((void)0)
#endif // _DEBUG

#define ensure(expression) (void)(!!(expression) || Crash())

inline void setaccuracy(const std::streamsize &accuracy)
{
  std::cout << std::fixed << std::setprecision(accuracy);
}

#define int long long
using namespace std;

int n,k;
pair<int,int>que[100010];
priority_queue<pair<double,pair<int,int>>,vector<pair<double,pair<int,int>>>,greater<pair<double,pair<int,int>>>>quee;
int lianl[100010],lianr[100010];
double suan(int x,int y){
  return (que[y].second-que[x].second)*1.0/(que[y].first-que[x].first);
}
void solve()
{
  
  cin>>n>>k;
  f(i,1,n)cin>>que[i].first>>que[i].second,lianl[i]=i-1,lianr[i]=i+1;
  f(i,2,n){
    quee.push({suan(i-1,i),{i-1,i}});
  }
  k=n-k;
  while(k--){
    auto op=quee.top();
    quee.pop();
    int L=lianl[op.second.first];
    int R=lianr[op.second.second];
    double a1=suan(L,op.second.second);
    double a2=suan(L,op.second.second);
    if(a1>a2){
      
      lianr[L]=lianr[op.second.first];
      lianl[op.second.second]=lianl[op.second.first];
      if(L==0)continue;
      quee.push({suan(L,op.second.second),{L,op.second.second}});
    }
    else {
      
      lianr[op.second.first]=lianr[op.second.second];
      lianl[R]=lianl[op.second.second];
      if(R==n)continue;
      quee.push({suan(op.second.first,R),{op.second.first,R}});
    }
  }
  cout<<fixed<<setprecision(7)<<quee.top().first<<endl;
}

signed main()
{
  // ios::sync_with_stdio(false);
  // std::cin.tie(nullptr);
  // std::cout.tie(nullptr);
  int T = 1;
  // cin >> T;
  // scanf(" %d", &T);
  // std::cin >> T;
  // for (int q = 1; q <= T; q++) {
  // while (T--) {
  solve();
  // }

  return 0;
}