#include<iostream>
#include<memory>
#include<algorithm>
#include<cstdio>
#include <functional>
using namespace std;
const int maxn=1001;
int cmp(const void *arg1,const void *arg2)
{
	return *(int *)arg1-*(int *)arg2;
}
int n,i,j,u,v;
int a[maxn],b[maxn];
int main(void)
{
	cin>>n;
	while(n>0)
	{
		for(i=0;i<n;i++)	cin>>a[i];
		memset(b,0,sizeof(b));
		//qsort(a,n,sizeof(int),cmp);
		sort(a,a+n);
		for(i=n-1;i>=3;i--)
			for(j=0;j<i;j++)
				if(a[j]*3>=a[i])
				{
					b[i]=j;break;
				}
		
		for(i=n-1;i>=3;i--)
			for(j=0;j<=b[i];j++)
				for(v=b[i];v<i;v++)
					for(u=j+1;u<v;u++)
						if(a[i]==a[j]+a[u]+a[v])
							goto output;

output:
			if(i==2)	cout<<"no solution\n";
			else	cout<<a[i]<<"\n";
		cin>>n;
	}
	return 0;
}