救我！

#include<bits/stdc++.h>
using namespace std;
const int maxn=5010;
double n,x[maxn],y[maxn],sl[maxn],b[maxn],l,r,ans;
bool check(double a){
	double h=-1e9,t=1e9;
	for(int i=2;i<=n;i++){
		if(sl[i]<0) h=max(h,(a-b[i])/sl[i]);
		else if(sl[i]>0) t=min(t,(a-b[i]/sl[i]));
		else{
			if(a<b[i]) return false;
		}
	}
	return h<=t;
}
int main(){
	scanf("%lf",&n);
	for(int i=1;i<=n;i++){
		scanf("%lf%lf",&x[i],&y[i]);
		sl[i]=(y[i]-y[i-1])/(x[i]-x[i-1]);
		b[i]=y[i]-sl[i]*x[i];
	}
	l=0,r=1e9;
	while(l<=r){
		double mid=(l+r)/2;
		if(check(mid)) ans=mid,r=mid-0.001;
		else l=mid+0.001;
	}
	printf("%.2f",ans);
	return 0;
}