slope

/*
 Author: 曹北健(37509)
 Result: AC Submission_id: 4162855
 Created at: Mon Mar 14 2022 21:23:04 GMT+0800 (China Standard Time)
 Problem: 5395  Time: 24    Memory: 5592
*/

#include <stdio.h>
double ans[1919810];
int main(){
 int n,x[1000],y[1000],i=0,j,k,l,m;


 scanf("%d",&n);

 while ((scanf("%d %d",&x[i],&y[i]))!=EOF){
  i++;
 }

 l=0;
 for(j=1;j<n;j++){
  for(k=0;k<j;k++){
   ans[l]=1.0*(y[j]-y[k])/(x[j]-x[k]);
   l++;
  }
 }

 double max=-1e12;
 for(m=0;m<l;m++){
  if(ans[m]>max){
   max=ans[m];
  }
 }
 printf("%.3f",max);
 return 0;
}