#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], be[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, be[i] = i - 1;

    set<PII> st;
    for (int i = 2; i <= n; i++) {
        st.insert({(y[i] - y[i - 1]) / (x[i] - x[i - 1]), i - 1});
    }
    for (int i = m + 1; i <= n; i++) {
        auto now = *st.begin();
//        cout<<now.first<<"\n";
        st.erase(now);
        int id = now.second;

        int bid = be[id];
        int nid = nxt[id];
        int nnid = nxt[nid];

        if (nnid <= n && bid >= 1) {
//            cout<<1<<"\n";
            double shanho = (y[nnid] - y[id]) / (x[nnid] - x[id]);

            double shanqian = (y[nid] - y[bid]) / (x[nid] - x[bid]);

            if (shanho >= shanqian) {
                st.erase({(y[nnid] - y[nid]) / (x[nnid] - x[nid]), nid});
                st.insert({(y[nnid] - y[id]) / (x[nnid] - x[id]), id});
                nxt[id] = nnid;
                be[nnid] = id;
            } else {
                st.erase({(y[id] - y[bid]) / (x[id] - x[bid]), bid});
                st.insert({(y[nid] - y[bid]) / (x[nid] - x[bid]), bid});
                nxt[id] = nid;
                be[nid] = id;
            }
        } else if (nnid <= n) {
            be[nid] = bid;
        } else if (bid >= 1) {
            nxt[id] = nnid;
        }

    }
    cout << (*st.begin()).first << "\n";
}

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