
void main()
{
   int n,i,j,a[300];
   float sum=0,ave;
   scanf("%d",&n);
   for (i=0;i<n;i++)
   {
   	   scanf("%d",&(a[i]));
   	   sum+=a[i];
   }
   ave=sum/n;
   for (i=n-1;i>0;i--)
   {
   	    for (j=0;j<i;j++)
   	    {
   	    	if (a[j]>a[j+1]) 
   	    	{
   	    		int tem;
   	    		tem=a[j];
   	    		a[j]=a[j+1];
   	    		a[j+1]=tem;
   	    	}
   	    }
   }
   if((2*ave-a[0]-a[n-1])>0)
   {
   	   for(i=0;i<n;i++)
   	  {
   	  	 if(a[i]==a[0])
   	      {
   	      	if (a[i+1]!=a[0]) printf("%d",a[i]);
   	      	else printf("%d,",a[i]);
   	      }
   	  }
   }
   if((2*ave-a[0]-a[n-1])<=0)
   {
   	  for(i=0;i<n;i++)
   	  {
   	  	 if((a[i]==a[n-1])||(a[i]+a[n-1])==2*ave)
   	      {
   	      	if (i==n-1) printf("%d",a[i]);
   	      	else printf("%d,",a[i]);
   	      }
   	  }
   }
}