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.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.*;

public class TaskC
{
	public static void main(String[] args)
	{
		new TaskC(System.in, System.out);
	}

	static class Solver implements Runnable
	{
		int h;
		int[] hts;
//		BufferedReader in;
		InputReader in;
		PrintWriter out;

		void solve() throws IOException
		{
			h = in.nextInt();
			hts = in.nextIntArray(h + 1);

			int pos = -1;

			for (int i = 1; i <= h; i++)
			{
				if (hts[i - 1] > 1 && hts[i] > 1)
				{
					pos = i - 1;

					break;
				}
			}

			if (pos == -1)
			{
				out.println("perfect");

				return;
			}

			out.println("ambiguous");

			List<Integer> list = new ArrayList<>();
			List<Integer> temp = new ArrayList<>();
			int ctr = 1;

			list.add(0);

			for (int i = 0; i <= h; i++)
			{
				for (int j = 0; j < hts[i]; j++)
				{
					out.print(list.get(0) + " ");
					temp.add(ctr++);
				}

				list = temp;
				temp = new ArrayList<>();
//				System.out.println("i : " + i + ", list : " + list);
			}

			out.println();

			list = new ArrayList<>();
			temp = new ArrayList<>();
			list.add(0);
			ctr = 1;

			for (int i = 0; i <= pos; i++)
			{
				for (int j = 0; j < hts[i]; j++)
				{
					out.print(list.get(0) + " ");
					temp.add(ctr++);
				}

				list = temp;
				temp = new ArrayList<>();
			}

			out.print(list.get(0) + " " + list.get(1) + " ");
			temp.add(ctr++);
			temp.add(ctr++);

			for (int i = pos + 1; i <= h; i++)
			{
				for (int j = (i == pos + 1 ? 2 : 0); j < hts[i]; j++)
				{
					out.print(list.get(0) + " ");
					temp.add(ctr++);
				}

				list = temp;
				temp = new ArrayList<>();
			}
		}

		void debug(Object... o)
		{
			System.err.println(Arrays.deepToString(o));
		}

//		uncomment below line to change to BufferedReader
//		public Solver(BufferedReader in, PrintWriter out)
		public Solver(InputReader in, PrintWriter out)
		{
			this.in = in;
			this.out = out;
		}

		@Override
		public void run()
		{
			try
			{
				solve();
			}
			catch (IOException e)
			{
				e.printStackTrace();
			}
		}

	}

	static class InputReader
	{
		private InputStream stream;
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;

		public int read()
		{
			if (numChars == -1)
				throw new InputMismatchException();

			if (curChar >= numChars)
			{
				curChar = 0;
				try
				{
					numChars = stream.read(buf);
				}
				catch (IOException e)
				{
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}

			return buf[curChar++];
		}

		public int nextInt()
		{
			int c = read();

			while (isSpaceChar(c))
				c = read();

			int sgn = 1;

			if (c == '-')
			{
				sgn = -1;
				c = read();
			}

			int res = 0;

			do
			{
				if (c < '0' || c > '9')
					throw new InputMismatchException();

				res *= 10;
				res += c & 15;

				c = read();
			} while (!isSpaceChar(c));

			return res * sgn;
		}

		public int[] nextIntArray(int arraySize)
		{
			int array[] = new int[arraySize];

			for (int i = 0; i < arraySize; i++)
				array[i] = nextInt();

			return array;
		}

		public long nextLong()
		{
			int c = read();

			while (isSpaceChar(c))
				c = read();

			int sign = 1;

			if (c == '-')
			{
				sign = -1;

				c = read();
			}

			long result = 0;

			do
			{
				if (c < '0' || c > '9')
					throw new InputMismatchException();

				result *= 10;
				result += c & 15;

				c = read();
			} while (!isSpaceChar(c));

			return result * sign;
		}

		public long[] nextLongArray(int arraySize)
		{
			long array[] = new long[arraySize];

			for (int i = 0; i < arraySize; i++)
				array[i] = nextLong();

			return array;
		}

		public float nextFloat()
		{
			float result, div;
			byte c;

			result = 0;
			div = 1;
			c = (byte) read();

			while (c <= ' ')
				c = (byte) read();

			boolean isNegative = (c == '-');

			if (isNegative)
				c = (byte) read();

			do
			{
				result = result * 10 + c - '0';
			} while ((c = (byte) read()) >= '0' && c <= '9');

			if (c == '.')
				while ((c = (byte) read()) >= '0' && c <= '9')
					result += (c - '0') / (div *= 10);

			if (isNegative)
				return -result;

			return result;
		}

		public double nextDouble()
		{
			double ret = 0, div = 1;
			byte c = (byte) read();

			while (c <= ' ')
				c = (byte) read();

			boolean neg = (c == '-');

			if (neg)
				c = (byte) read();

			do
			{
				ret = ret * 10 + c - '0';
			} while ((c = (byte) read()) >= '0' && c <= '9');

			if (c == '.')
				while ((c = (byte) read()) >= '0' && c <= '9')
					ret += (c - '0') / (div *= 10);

			if (neg)
				return -ret;

			return ret;
		}

		public String next()
		{
			int c = read();

			while (isSpaceChar(c))
				c = read();

			StringBuilder res = new StringBuilder();

			do
			{
				res.appendCodePoint(c);

				c = read();
			} while (!isSpaceChar(c));

			return res.toString();
		}

		public String nextLine()
		{
			int c = read();

			StringBuilder result = new StringBuilder();

			do
			{
				result.appendCodePoint(c);

				c = read();
			} while (!isNewLine(c));

			return result.toString();
		}

		public boolean isNewLine(int c)
		{
			return c == '\n';
		}

		public boolean isSpaceChar(int c)
		{
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		public void close()
		{
			try
			{
				stream.close();
			}
			catch (IOException e)
			{
				e.printStackTrace();
			}
		}

		public InputReader(InputStream stream)
		{
			this.stream = stream;
		}

	}

	static class CMath
	{
		static long power(long number, long power)
		{
			if (number == 1 || number == 0 || power == 0)
				return 1;

			if (power == 1)
				return number;

			if (power % 2 == 0)
				return power(number * number, power / 2);
			else
				return power(number * number, power / 2) * number;
		}

		static long modPower(long number, long power, long mod)
		{
			if (number == 1 || number == 0 || power == 0)
				return 1;

			number = mod(number, mod);

			if (power == 1)
				return number;

			long square = mod(number * number, mod);

			if (power % 2 == 0)
				return modPower(square, power / 2, mod);
			else
				return mod(modPower(square, power / 2, mod) * number, mod);
		}

		static long moduloInverse(long number, long mod)
		{
			return modPower(number, mod - 2, mod);
		}

		static long mod(long number, long mod)
		{
			return number - (number / mod) * mod;
		}

		static int gcd(int a, int b)
		{
			if (b == 0)
				return a;
			else
				return gcd(b, a % b);
		}

		static long min(long... arr)
		{
			long min = arr[0];

			for (int i = 1; i < arr.length; i++)
				min = Math.min(min, arr[i]);

			return min;
		}

		static long max(long... arr)
		{
			long max = arr[0];

			for (int i = 1; i < arr.length; i++)
				max = Math.max(max, arr[i]);

			return max;
		}

		static int min(int... arr)
		{
			int min = arr[0];

			for (int i = 1; i < arr.length; i++)
				min = Math.min(min, arr[i]);

			return min;
		}

		static int max(int... arr)
		{
			int max = arr[0];

			for (int i = 1; i < arr.length; i++)
				max = Math.max(max, arr[i]);

			return max;
		}

	}

	public TaskC(InputStream inputStream, OutputStream outputStream)
	{
//		uncomment below line to change to BufferedReader
//		BufferedReader in = new BufferedReader(new InputStreamReader(inputStream));
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		Thread thread = new Thread(null, new Solver(in, out), "TaskC", 1 << 29);

		try
		{
			thread.start();
			thread.join();
		}
		catch (InterruptedException e)
		{
			e.printStackTrace();
		}
		finally
		{
			in.close();
			out.flush();
			out.close();
		}
	}

}

/*

5
1 1 3 4 5 6

4
1 1 3 4 2

*/