#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-10;
const double INF = 1e12;

const int MAXN = 1e5 + 10;
int n, k;
pair<double, double> p[MAXN];

int check(double mid) {
    multiset<double> st;
    for (int i = n; i >= 1; i--) {
        auto [x, y] = p[i];
        int cnt = distance(st.begin(), st.upper_bound(y - mid * x));
        if (cnt + 1 >= k) return 1;
        st.insert(y - mid * x);
    }
    return 0;
}

int main() {
    // ios::sync_with_stdio(false);
    // cin.tie(0); cout.tie(0);
    cin >> n >> k;
    for (int i = 1; i <= n; i++) {
        auto &[x, y] = p[i];
        cin >> x >> y;
    }
    double L = -INF, R = INF;
    while (R - L >= eps) {
        double mid = (L + R) / 2;
        if (check(mid)) R = mid;
        else L = mid;
    }
    printf("%.10lf\n", R);
    return 0;
}