#include <bits/stdc++.h>

void Yes() {
    std::cout << "YES" << "\n";
    return;
}

void No() {
    std::cout << "NO" << "\n";
    return;
}

template<typename T>
void out(T x) { std::cout << x << "\n"; }

using namespace std;
using ll = long long;
using PII = pair<double, int>;

const int N = 2e5 + 10;
int nxt[N];
double x[N], y[N];
void Solve() {
    ll n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
        cin >> x[i] >> y[i] , nxt[i] = i + 1;
    priority_queue<PII, vector<PII>, greater<PII>> q;

    for (int i = 2; i <= n; i++) {
        q.push({(y[i] - y[i - 1]) / (x[i] - x[i - 1]), i - 1 });
    }
    for (int i = m + 1; i<= n; i++) {
        auto now = q.top();
        q.pop();
        int id = now.second;
//        cout<<now.first<<"\n";
        nxt[id] = nxt[nxt[id]];
        if(nxt[id] <= n)
        q.push({(y[nxt[id]] - y[id]) / (x[nxt[id]] - x[id]),id});
    }
    cout<<q.top().first<<"\n";
}

signed main() {
    cout<<fixed<<setprecision(10);
    int t = 1;
//    cin>>t;
    while (t--)
        Solve();
}