/*

zju 1101 Gamblers

00:02.01 448k

2004.08.09 by adai

*/

#include <iostream>

#include <cstdlib>

#include <string>

#include <cstdio>

using namespace std;

int cmp(const void *t1,const void *t2)

{

int *a,*b;

a=(int *)t1;

b=(int *)t2;

if((*a)-(*b)>0) return 1;

if((*a)-(*b)<0) return -1;

return 0;

}

int wager[1000];

int main() {

int n;

while (1) {

scanf("%d", &n);

if (n == 0) break;

for (int i = 0; i < n; i ++) {

scanf("%d", &wager[i]);

}

qsort(wager, n, sizeof(int), cmp);

for (int i = n - 1; i >= 0; i --) {

for (int j = 0; j < n; j ++) {

if (j == i) continue;

for (int t = j + 1; t < n; t ++) {

if (t == i) continue;

for (int s = t + 1; s < n; s ++) {

if (s == i) continue;

if (wager[j] + wager[t] + wager[s] == wager[i]) {

printf("%d\n", wager[i]);

goto exit;

}

}

}

}

}

printf("no solution\n");

exit:;

}

return 0;

}