#include<bits/stdc++.h> 
using namespace std;
long long a[1000001],n;
inline int read()
{
	int x=0;bool flag=1;char ch=getchar();
	while(ch<'0'||ch>'9') {if(ch=='-')flag=0;ch=getchar();}
	while(ch>='0'&&ch<='9') {x=(x<<3)+(x<<1)+ch-'0';ch=getchar();}
	if(flag) return x;
	return ~(x-1);
} 
int main()
{
	freopen("Unnamed_Problem.in","r",stdin);
	freopen("Unnamed_Problem.out","w",stdout);
    n=read();
    for(int i=1;i<=n;i++)
    	a[i]=read();
    sort(a+1,a+1+n);
    long long ans;
    ans=min(a[1]-a[n]*a[n]/(4*a[2]),a[2]-a[n]*a[n]/(4*a[1]));
    cout<<ans<<endl;
    return 0;
}