#include<bits/stdc++.h>
using namespace std;
int n;
int main(void)
{
    freopen("Unnamed_Problem.in","r",stdin);
    freopen("Unnamed_Problem.out","w",stdout);
    long long a=1000001,b,c=0;
    scanf("%d",&n);
    for(int i=1;i<=n;++i)
    {
        long long x;
     scanf("%lld",&x);
     if(x<a)
     {
        c=a;
        a=x; 
     }
     if(x>b)
     {
         b=x;
     }
     if(x>a&&x<c)
     {
         c=x;
     }
    }
    long long ans;
    ans=c-b*b/(a*4);
    printf("%lld",ans);
    return 0;
}