#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<queue>
#include<cmath>
#include<stack>
#include<vector>
#include<map>
#define ll long long
#define lowbit(x) x&(-x)
using namespace std;
int n,k;
double eps=1e-12,g[500005],a[500005];
int f[500005];
struct node{
	ll x,y;
}p[500005];
bool check(double x){
	for(int i=1;i<=n;++i) a[i]=p[i].y-x*p[i].x,g[i]=0;
	f[1]=1;
	g[1]=a[1];
	g[0]=1e18;
	int cnt=1;
	for(int i=2;i<=n;++i){
		int l=0,r=cnt+1;
		while(l<r){
			int mid=(l+r)/2;
			if(g[mid]>=a[i]) l=mid+1;
			else r=mid;
		}
		f[i]=l;
		g[l]=max(g[l],a[i]);
		cnt=max(cnt,f[i]);
	}
	if(cnt>=k) return 1;
	return 0;
}
int main(){
	scanf("%d%d",&n,&k);
	for(int i=1;i<=n;++i){
		scanf("%lld%lld",&p[i].x,&p[i].y);
	}
	double l=-1e9,r=1e9;
	while(l+eps<r){
		double mid=(l+r)/2.0;
		if(check(mid)) r=mid;
		else l=mid;
	}
	printf("%.12lf",l);
}