#include<bits/stdc++.h>
using namespace std;

#define INF 0x3f3f3f3f3f3f3f3f
#define pii pair<int,int>
#define fi first
#define se second
#define all(_a) _a.begin(), _a.end()
#define rep(i,p,q) for (int i=(p);i<=(q);i++)
const int N=1e5+5; const double eps=1e-10; int n,k; double b[N],f[N]; struct node{int x,y;}a[N];
int check(double x) {
    int l;
    rep(i,1,n) b[i]=a[i].y-a[i].x*x;
    f[1]=b[1],l=1;
    rep(i,2,n) 
        if (b[i]>f[l]) f[++l]=b[i];
        else {
            for (int p=1,q=l;p<q;) {
                int mid=p+q>>1;
                if (f[mid]>=b[i]) q=mid;
                else p=mid+1;
            }
            f[l]=b[i];
        }
    return l>=k;
}
signed main(){
    double s;
    scanf("%d%d",&n,&k);
    rep(i,1,n) scanf("%d%d",&a[i].x,&a[i].y);
    //sort(a+1,a+1+n,[](node a,node b){return a.x<b.x;});
    double l=-2e9,r=2e9;
    for (;r-l>eps;) {
        double mid=(l+r)/2;
        if (check(mid)) s=mid,l=mid+eps;
        else r=mid-eps;
    }
    printf("%.8lf",s);
    return 0;
}