Problem: Sasha is taking part in a programming competition. In one of the problems she should check if some rooted trees are isomorphic or not. She has never seen this problem before, but, being an experienced participant, she guessed that she should match trees to some sequences and then compare these sequences instead of trees. Sasha wants to match each tree with a sequence a0, a1, ..., ah, where h is the height of the tree, and ai equals to the number of vertices that are at distance of i edges from root. 

Unfortunately, this time Sasha's intuition was wrong, and there could be several trees matching the same sequence. To show it, you need to write a program that, given the sequence ai, builds two non-isomorphic rooted trees that match that sequence, or determines that there is only one such tree.

Two rooted trees are isomorphic, if you can reenumerate the vertices of the first one in such a way, that the index of the root becomes equal the index of the root of the second tree, and these two trees become equal.

The height of a rooted tree is the maximum number of edges on a path from the root to any other vertex.

Input

The first line contains a single integer h (2 ≤ h ≤ 105) — the height of the tree.

The second line contains h + 1 integers — the sequence a0, a1, ..., ah (1 ≤ ai ≤ 2·105). The sum of all ai does not exceed 2·105. It is guaranteed that there is at least one tree matching this sequence.

Output

If there is only one tree matching this sequence, print "perfect".

Otherwise print "ambiguous" in the first line. In the second and in the third line print descriptions of two trees in the following format: in one line print <image> integers, the k-th of them should be the parent of vertex k or be equal to zero, if the k-th vertex is the root.

These treese should be non-isomorphic and should match the given sequence.

Examples

Input

2
1 1 1


Output

perfect


Input

2
1 2 2


Output

ambiguous
0 1 1 3 3
0 1 1 3 2

Note

The only tree in the first example and the two printed trees from the second example are shown on the picture:

<image>

Solution (in JAVA):

Solution:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Random;
import java.util.StringTokenizer;


public class Main {

	static boolean visited[] ; 
	static boolean ends[] ;
	static long mod = 1000000007 ;
	static int lens[] ; 
	static int seeds[] ; 
	static char a[] ;
	static double total ; 
	public static ArrayList adj[] ; 
	public static long x,y ;
	public static ArrayList<Integer> xx ;	
	public static double dp[][][] ;
	public static void main(String[] args) throws IOException, InterruptedException {
		Scanner sc =  new Scanner(System.in) ;
		PrintWriter pw = new PrintWriter(System.out);

		int h = sc.nextInt() ; 
		int a[] = new int[h+1]; 
		for (int i = 0; i < a.length; i++)
		{
			a[i]=sc.nextInt() ;
		}
		boolean f = false ;
		for (int i = 0; i < a.length-1; i++)
		{
			if(a[i]>1 && a[i+1]>1)
				f=true ;
		}

		if(f==false)
		{System.out.println("perfect"); return ;}
		else
			System.out.println("ambiguous");

		int sum =0 ;
		for (int i = 0; i < a.length; i++)
		{
			sum += a[i];
		}
		int d = 0 ;
		for (int i = 0 ;i<a.length; i++)
		{
			if(a[i]==1)
			{System.out.print(d+" ");d++;}
			else
			{
				for (int j = 0; j < a[i]; j++)
				{
					System.out.print(d+" ");
				}
				d += a[i];
			}

		}
		System.out.println();
		d=0;
		for (int i = 0 ;i<a.length; i++)
		{
			if(a[i]==1)
			{System.out.print(d+" ");d++;}
			else if(a[i]!=1 && a[i-1]==1)
			{
				for (int j = 0; j < a[i]; j++)
				{
					System.out.print(d+" ");
				}
				d += a[i];
			}else if(a[i]!=1 && a[i-1]>1)
			{
				for (int j = 0; j < a[i]-1; j++)
				{
					System.out.print(d+" ");
				}
				System.out.print((d-1)+" ");
				d += a[i];
			}

		}




	}
	public static boolean isVow(char a)
	{
		if(a=='a' || a=='e' || a=='o' || a=='u' || a=='i' )
			return true; 
		else return false; 
	}





	static boolean contains(int p[], int x)
	{

		for (int i = 0; i < p.length; i++)
		{
			if(x==p[i]) return true ;
		}
		return false; 
	}
	static void generate(int n)
	{
		if(n>=10000000)
			return ; 

		xx.add(n) ; 
		generate(Integer.parseInt("4"+n)) ;
		generate(Integer.parseInt("7"+n)) ;

	}


	static long pow(long base, int exp) {
		long res = 1;
		while(exp > 0) {
			if(exp % 2 == 1) {
				res = (res * base);
			}

			base = (base * base) ;
			exp /= 2;
		}

		return res;
	}
































	public static void dfss(int root , int len)
	{
		visited[root]=true ; 
		if(ends[root] && root!=0) lens[root] = len ; 

		for (int i = 0; i < adj[root].size(); i++)
		{
			int c= (int) adj[root].get(i) ; 
			if(visited[c]==false)
				dfss(c, len+1);
		}
	}

	public static void pr(int root ,  int seed){
		visited[root] = true ;
		int dv = adj[root].size()-1 ; 
		if(root==0) dv++ ;

		for (int i = 0; i < adj[root].size(); i++)
		{
			int c = (int)adj[root].get(i) ; 
			seeds[c]=dv*seed ;
		}

		for (int i = 0; i < adj[root].size() ; i++)
		{
			int c = (int)adj[root].get(i) ; 
			if(visited[c]==false)
				pr(c , seeds[c]);

		}

	}



	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

		public int[] nextIntArray(int n) throws IOException {
			int arr[] = new int[n];
			for (int i = 0; i <n ; i++)
			{
				arr[i] = Integer.parseInt(next());
			}
			return arr;
		}
		public long[] nextLongArray(int n) throws IOException {
			long arr[] = new long[n];
			for (int i = 0; i <n ; i++)
			{
				arr[i] = Long.valueOf(next());
			}
			return arr;
		}
	}


	public static long getGCD(long n1, long n2) {
		if (n2 == 0) {
			return n1;
		}
		return getGCD(n2, n1 % n2);
	}


	public static void shuffleA(ArrayList<Integer> ss){
		if(ss.size()==1)
			return ; 
		for (int i = 0; i < ss.size(); i++)
		{
			Random rand = new Random();

			int  n = rand.nextInt(ss.size()-1) + 0;

			int tmp = ss.get(n);
			ss.remove(n);
			ss.add(tmp);
		}
	}
	public static void shuffle(int[]x){
		if(x.length==1)
			return ; 
		for (int i = 0; i < x.length; i++)
		{
			Random rand = new Random();

			int  n = rand.nextInt(x.length-1) + 0;

			int tmp = x[n];
			x[n]=x[i] ;
			x[i]=tmp;
		}
	}
	public static int binaryy(int[] arr, int l, int r, int x)   /// begin by 0 and n-1
	{
		if (r>=l)
		{
			int mid = l + (r - l)/2;
			if (arr[mid]== x)
				return mid;
			if (arr[mid]> x)
				return binaryy(arr, l, mid-1, x);
			return binaryy(arr, mid+1, r, x);
		}
		return -1;
	}

	/// searching for the index of first elment greater than x
	public static int binary1(int[]arr , int x) {
		int low = 0, high = arr.length; // numElems is the size of the array i.e arr.size() 
		while (low != high) {
			int mid = (low + high) / 2; // Or a fancy way to avoid int overflow
			if (arr[mid] <= x) {
				/* This index, and everything below it, must not be the first element
				 * greater than what we're looking for because this element is no greater
				 * than the element.
				 */
				low = mid + 1;
			}
			else {
				/* This element is at least as large as the element, so anything after it can't
				 * be the first element that's at least as large.
				 */
				high = mid;
			}
		}
		return low ; // return high ; 
	}


	////// searching for last element less than X 
	//	public static int binary2(pair[]arr , int x) {
	//		int low = 0, high = arr.length; // numElems is the size of the array i.e arr.size() 
	//		while (low != high) {
	//			int mid = (low + high) / 2; // Or a fancy way to avoid int overflow
	//			if (arr[mid].x >= x) {
	//				/* This index, and everything below it, must not be the first element
	//				 * greater than what we're looking for because this element is no greater
	//				 * than the element.
	//				 */
	//				high=mid;
	//			}
	//			else {
	//				/* This element is at least as large as the element, so anything after it can't
	//				 * be the first element that's at least as large.
	//				 */
	//				low = mid+1 ; 
	//			}
	//		}
	//		return low ; // return high ; 
	//	}







	public static int binary(long []arr , long target , int low , long shift) {
		int high = arr.length; 
		while (low != high) {
			int mid = (low + high) / 2; 
			if (arr[mid]-shift <= target) {
				low = mid + 1;
			}
			else {
				high = mid;
			}
		}
		return low ; // return high ; 
	}
	public static boolean isLetter(char x){
		if(x+0 <=122 && x+0 >=97 )
			return true ;
		else if (x+0 <=90 && x+0 >=65 )
			return true ; 
		else return false; 
	}
	public static long getPrimes(long x ){
		if(x==2 || x==3 || x==1)
			return 2 ;
		if(isPrime(x))
			return 5 ;
		for (int i = 2; i*i<=x; i++)
		{
			if(x%i==0 && isPrime(i))
				return getPrimes(x/i) ;
		}
		return -1;
	}







	public static int lis( int[]a , int n){
		int lis[] = new int[n] ; 
		Arrays.fill(lis,1) ; 

		for(int i=1;i<n;i++)
			for(int j=0 ; j<i; j++)
				if (a[i]>a[j] &&  lis[i] < lis[j]+1)   
					lis[i] = lis[j] + 1;           

		int max = lis[0];

		for(int i=1; i<n ; i++)
			if (max < lis[i])
				max = lis[i] ;
		return (max);

		//			ArrayList<Integer> s = new ArrayList<Integer>() ;
		//			for (int i = n-1; i >=0; i--)
		//			{
		//				if(lis[i]==max)
		//				{
		//					s.add(a[i].z);
		//					max --; 
		//				}
		//			}
		//
		//			for (int i = s.size()-1 ; i>=0 ;  i--)
		//			{
		//				System.out.print(s.get(i)+" ");
		//			}
		//
	}
	public static int calcDepth(Vertix node){
		if(node.depth>0) return node.depth; 
		// meaning it has been updated before;
		if(node.parent != null)
			return 1+ calcDepth(node.parent);
		else
			return -1;
	}

	public static boolean isPrime (long num){
		if (num < 2) return false;
		if (num == 2) return true;
		if (num % 2 == 0) return false;
		for (int i = 3; i * i <= num; i += 2)
			if (num % i == 0) return false;
		return true;
	}


	public static ArrayList<Long> getDiv(Long n)
	{
		ArrayList<Long>  f = new ArrayList<Long>() ; 

		while (n%2==0)
		{
			if(!f.contains(2l))
			{f.add((long) 2) ;}
			n /= 2;
		}

		// n must be odd at this point.  So we can
		// skip one element (Note i = i +2)
		for (long i = 3; i <= Math.sqrt(n); i+= 2)
		{
			// While i divides n, print i and divide n
			while (n%i == 0)
			{
				if(!f.contains(i))f.add(i);
				n /= i;
			}
		}

		// This condition is to handle the case whien
		// n is a prime number greater than 2
		if (n > 2)
			if(!f.contains(n))f.add(n);


		return f ;



	}

	//		public static boolean dfs(Vertix v , int target){
	//			try{
	//				visited[v.i]= true ;
	//			} catch (NullPointerException e)
	//			{
	//				System.out.println(v.i);
	//			}
	//			if(v.i == target)
	//
	//				return true ;
	//			for (int i =0 ; i< v.neighbours.size() ; i++)
	//			{ 
	//
	//				Vertix child = v.neighbours.get(i) ;
	//				if(child.i == target){
	//					found = true  ; 
	//				}
	//				if(visited[child.i]==false){
	//					found |= dfs(child, target) ;
	//				}
	//			}
	//			return found; 
	//		}









	public static class Vertix{
		long i ; 
		int depth ;
		ArrayList<Vertix> neighbours ; 
		Vertix parent ; 
		Vertix child ; 


		public Vertix(long i){
			this.i = i ;
			this.neighbours = new ArrayList<Vertix> () ;
			this.parent = null ;
			depth =-1;
			this.child = null ;
		}
	}

	public static class pair implements Comparable<pair> {
		int x ; 
		int y ; 




		public pair(int x, int y ){

			this.x=x ; 
			this.y =y ;


		}


		@Override
		public int compareTo(pair p) {
			if(this.y-this.x > p.y-p.x)
				return 1 ; 
			else if (this.y-this.x == p.y-p.x) 
				return 0 ; 
			else 
				return -1 ;
		}




	}

	public static class pair2 implements Comparable<pair2>{
		int i ; 
		int j ;
		int plus ;

		public pair2(int i , int j , int plus){
			this.i =i ;
			this.j = j ; 
			this.plus = plus ;
		}

		@Override
		public int compareTo(pair2 p) {
			if(this.j > p.j)
				return 1 ; 
			else if (this.j == p.j) return 0 ;
			else 
				return -1 ;
		}


	}
	public static class point implements  Comparable<point>
	{
		int x, y ; 
		public point(int x,int y){
			this.x=x ; this.y=y;
		}
		@Override
		public boolean equals(Object o) {

			// If the object is compared with itself then return true  
			if (o == this) {
				return true;
			}

			/* Check if o is an instance of Complex or not
	          "null instanceof [type]" also returns false */
			if (!(o instanceof point)) {
				return false;
			}

			// typecast o to Complex so that we can compare data members 
			point c = (point) o;

			// Compare the data members and return accordingly 
			return Integer.compare(x, c.x) == 0
					&& Integer.compare(y, c.y) == 0;
		}
		@Override
		public int compareTo(point p) {
			if(this.x == p.x && this.y ==p.y)
				return 0 ; 
			else
				return -1 ; 
		}

		@Override
		public int hashCode()
		{
			return 15+x+(y%2) ;
		}



	}


}