include<iostream>
using namespace std;
int main(){
int a[100000];
unsigned long int b;
unsigned long int c;
unsigned long int x;
unsigned long int l=0;
while(b!=0){
scanf("%d",b);
if(b!=0){
for(int i=1;i<b+1;i++){
scanf("%d",c);
a[i]=c;
}
for(int m=1;m<b+1;m++){
x=a[m];
if(a[x]==m){
l++;
}
}
if(l==b){
cout<<"\n ambiguous";
}
else{cout<<"\n not ambiguous";
}
l=0;
}
else{break;}
}
return 0;
}