/*
直接模拟
*/
#define LOCAL
#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<cstdlib>
#include<iomanip>
#include<string>
#include<algorithm>
#include<ctime>
#include<stack>
#include<queue>
#include<vector>
#define N 100005
using namespace std;
int a[N],b[N];
bool match(int len)
{
     int i;
     for(i=0;i<len;i++)
        if(a[i]!=b[i])
            return false;
     return true;     
}
int main()
{
#ifdef LOCAL
       freopen("input.txt","r",stdin);
       freopen("output.txt","w",stdout);
#endif
 
      int i,len;
      while(cin>>len&&len)
      {
          for(i=0;i<len;i++) 
          {cin>>a[i];b[a[i]-1]=i+1;}
          if(match(len))cout<<"ambiguous"<<endl;
          else cout<<"not ambiguous"<<endl;                   
      }
      return 0;
}