#include <iostream>

 #include <cstdio>

 #include <cstdlib>

 #include <cstring>

 using namespace std;

 const int maxn =  + ;

 char s[maxn], t[maxn];

 int cnt[maxn];

 void solve()

 {

     int ls = strlen(s);

     int lt = strlen(t);

     memset(cnt, , sizeof(cnt));

     for (int i = ; i < ls; i++)

         cnt[s[i]-'a']++;

     for (int i = ; i < lt; i++)

         cnt[t[i]-'a']--;

     int aut, arr, both;

     aut = arr = both = ;

     for (int i = , j = ; i < ls; i++)

     {

         if (s[i] == t[j])

             j++;

         if (j == lt)

         {

             aut ^= ;

             break;

         }

     }

     for (int i = ; i < ; i++)

     {

         arr &= (cnt[i] == );

         both &= (cnt[i] >= );  // 这个“=”很重要，因为有可能s中有的字母t没有！

     }

     if (!aut)

         printf("automaton\n");

     else if (arr)

         printf("array\n");

     else if (both)

         printf("both\n");

     else

         printf("need tree\n");

 }

 int main()

 {

     while (scanf("%s%s", s, t) != EOF)

     {

         solve();

     }

     return ;

 }