#include <iostream>
using namespace std;
 
int main() {
    int a=1, i, arr[100005], arrInv[100005], not_amb;
    while(a!=0) {
    	cin>>a;
        not_amb=0; 
        for(i=1; i<=a; i++) {
            cin>>arr[i];
        }
        for(i=1; i<=a; i++) {
            arrInv[arr[i]]=i;
        }
        for(i=1; i<=a; i++) {
            if(arr[i]!=arrInv[i]) not_amb=1;
        }
        if(a!=0) {
        	if(not_amb) cout<<"not ambiguous"<<endl;
        	else cout<<"ambiguous"<<endl;
        }
    }    
    return 0;
}

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4
1 4 3 2
5
2 3 4 5 1
1
1
7
6 3 7 2 1 4 5
5
4 1 3 2 5
5
1 3 5 4 2
5
2 5 3 1 4
5
2 5 1 3 4
0