Problem: This is an interactive problem.

Little Dormi was faced with an awkward problem at the carnival: he has to guess the edges of an unweighted tree of n nodes! The nodes of the tree are numbered from 1 to n.

The game master only allows him to ask one type of question:

  * Little Dormi picks a node r (1 ≤ r ≤ n), and the game master will reply with an array d_1, d_2, …, d_n, where d_i is the length of the shortest path from node r to i, for all 1 ≤ i ≤ n.



Additionally, to make the game unfair challenge Little Dormi the game master will allow at most ⌈n/2⌉ questions, where ⌈ x ⌉ denotes the smallest integer greater than or equal to x.

Faced with the stomach-churning possibility of not being able to guess the tree, Little Dormi needs your help to devise a winning strategy!

Note that the game master creates the tree before the game starts, and does not change it during the game.

Input

The first line of input contains the integer n (2 ≤ n ≤ 2 000), the number of nodes in the tree.

You will then begin interaction.

Output

When your program has found the tree, first output a line consisting of a single "!" followed by n-1 lines each with two space separated integers a and b, denoting an edge connecting nodes a and b (1 ≤ a, b ≤ n). Once you are done, terminate your program normally immediately after flushing the output stream.

You may output the edges in any order and an edge (a,b) is considered the same as an edge (b,a). Answering is not considered as a query.

Interaction

After taking input, you may make at most ⌈n/2⌉ queries. Each query is made in the format "? r", where r is an integer 1 ≤ r ≤ n that denotes the node you want to pick for that query.

You will then receive n space separated integers d_1, d_2, …, d_n, where d_i is the length of the shortest path from node r to i, followed by a newline.

After printing a query do not forget to output end of line and flush the output. Otherwise, you will get Idleness limit exceeded. To do this, use:

  * fflush(stdout) or cout.flush() in C++; 
  * System.out.flush() in Java; 
  * flush(output) in Pascal; 
  * stdout.flush() in Python; 
  * see documentation for other languages. 



If at any point you make an invalid query or try to make more than ⌈ n/2 ⌉ queries, the interaction will terminate immediately and you will receive a Wrong Answer verdict.

Hacks

To hack a solution, use the following format.

The first line contains the integer n (2 ≤ n ≤ 2 000).

The next n−1 lines contain two integers u and v (1 ≤ u,v ≤ n) denoting an edge between u and v (u ≠ v). These n-1 edges must form a tree.

Examples

Input


4

0 1 2 2

1 0 1 1

Output


? 1

? 2

!
4 2
1 2
2 3


Input


5

2 2 1 1 0


Output


? 5

!
4 5
3 5
2 4
1 3

Note

Here is the tree from the first example.

<image>

Notice that the edges can be output in any order.

Additionally, here are the answers for querying every single node in example 1:

  * 1: [0,1,2,2] 
  * 2: [1,0,1,1] 
  * 3: [2,1,0,2] 
  * 4: [2,1,2,0]



Below is the tree from the second example interaction.

<image>

Lastly, here are the answers for querying every single node in example 2:

  * 1: [0,4,1,3,2] 
  * 2: [4,0,3,1,2] 
  * 3: [1,3,0,2,1] 
  * 4: [3,1,2,0,1] 
  * 5: [2,2,1,1,0]

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;
import java.math.*;
import java.math.BigInteger; 
//import javafx.util.*; 
public final class B
{    
	static PrintWriter out = new PrintWriter(System.out); 
	static StringBuilder ans=new StringBuilder();
	static FastReader in=new FastReader();
	static ArrayList<Integer> g[],og[];
	static long mod=(long)(1e9+7);
	static int D1[],D2[],par[];
	static boolean set[];
	static int value[];
	static long INF=Long.MAX_VALUE;
	static int N,M;
	static int val[],tot[],max[];
	static int min;
	static int dp1[][],dp2[][],path1[][],path2[][],two[][],five[][];
	static int path[][],A[];
	public static void main(String args[])throws IOException
	{
		int N=i();
		int A[]=ask(1,N);
		int D[]=new int[N+5];
		int dp[][]=new int[2][N+5];
		int par[]=new int[N+5];
		boolean edge[][]=new boolean[N+5][N+5];
		HashMap<Integer,ArrayList<Integer>> mp=new HashMap<>();
		for(int i=0; i<N; i++)
		{
			if(A[i]==1)
			{
				edge[1][i+1]=true;
				edge[i+1][1]=true;
			}
			D[A[i]]++;
			ArrayList<Integer> X=mp.getOrDefault(A[i], new ArrayList<Integer>());
			X.add(i+1);
			mp.put(A[i], X);
		}
		ArrayList<Integer> B=new ArrayList<>();
		f(dp,0,D,par);
		int d=par[0];
		while(D[d]>0)
		{
			//add entire arrayList here
			for(int x:mp.get(d))
				B.add(x);
			d+=par[d];
		}
		while(B.size()>0)
		{
			int a=B.remove(0);
			 A=ask(a,N);
			 for(int i=0; i<N; i++)
			 {
				 if(A[i]==1)
				 {
					 edge[i+1][a]=true;
					 edge[a][i+1]=true;
				 }
			 }
		}
		for(int i=1; i<=N; i++)
		{
			for(int j=1; j<=N; j++)
			{
				if(edge[i][j])
				{
					ans.append(i+" "+j+"\n");
					edge[i][j]=false;
					edge[j][i]=false;
				}
			}
		}
		System.out.println("!");
		System.out.println(ans);

	}
	static void f(int dp[][],int d,int A[],int par[])
	{
		if(A[d]==0)return ;
		f(dp,d+1,A,par);
		dp[0][d]=A[d]+Math.min(dp[0][d+1], dp[1][d+1]);
		if(dp[0][d+1]<dp[1][d+1])
		{
			par[d]=1;
		}
		else par[d]=2;
		dp[1][d]=dp[0][d+1];

	}
	static int [] ask(int a,int N)
	{
		System.out.println("? "+a);
		int A[]=input(N);
		return A;
	}
	static boolean isPalin(char X[])
	{
		int l=0,r=X.length-1;
		while(l<=r)
		{
			if(X[l]!=X[r])return false;
			l++;
			r--;
		}
		return true;
	}

	static boolean isSorted(int A[])
	{
		int N=A.length;
		for(int i=0; i<N-1; i++)
		{
			if(A[i]>A[i+1])return false;
		}

		return true;		
	}
	static int f1(int x,ArrayList<Integer> A)
	{
		int l=-1,r=A.size();
		while(r-l>1)
		{
			int m=(l+r)/2;
			int a=A.get(m);
			if(a<x)l=m;
			else r=m;
		}		
		return l;
	}






	static int max(int a,int b,int c)
	{
		return Math.max(a, Math.max(c, b));
	}
	static int value(char X[],char Y[])
	{
		int c=0;
		for(int i=0; i<7; i++)
		{
			if(Y[i]=='1' && X[i]=='0')return -1;
			if(X[i]=='1' && Y[i]=='0')c++;
		}
		return c;
	}
	static boolean isValid(int i,int j)
	{
		if(i<0 || i>=N)return false;
		if(j<0 || j>=M)return false;
		return true;
	}

	static long fact(long N)
	{
		long num=1L;
		while(N>=1)
		{
			num=((num%mod)*(N%mod))%mod;
			N--;
		}
		return num;
	}
	static boolean reverse(long A[],int l,int r)
	{
		while(l<r)
		{
			long t=A[l];
			A[l]=A[r];
			A[r]=t;
			l++;
			r--;
		}
		if(isSorted(A))return true;
		else return false;
	}
	static boolean isSorted(long A[])
	{
		for(int i=1; i<A.length; i++)if(A[i]<A[i-1])return false;
		return true;
	}
	static boolean isPalindrome(char X[],int l,int r)
	{
		while(l<r)
		{
			if(X[l]!=X[r])return false;
			l++; r--;
		}
		return true;
	}

	static long min(long a,long b,long c)
	{
		return Math.min(a, Math.min(c, b));
	}

	static void print(int a)
	{
		System.out.println("! "+a);
	}
	static int find(int a)
	{
		if(par[a]<0)return a;
		return par[a]=find(par[a]);
	}
	static void union(int a,int b)
	{
		a=find(a);
		b=find(b);
		if(a!=b)
		{
			par[a]+=par[b]; //transfers the size
			par[b]=a;       //changes the parent
		}
	}
	static void swap(char A[],int a,int b)
	{
		char ch=A[a];
		A[a]=A[b];
		A[b]=ch;
	}

	static void sort(long[] a) //check for long
	{
		ArrayList<Long> l=new ArrayList<>();
		for (long i:a) l.add(i);
		Collections.sort(l);
		for (int i=0; i<a.length; i++) a[i]=l.get(i);
	}
	static void setGraph(int N)
	{
		g=new ArrayList[N+1];		
		og=new ArrayList[N+1];

		val=new int[N+1];
		for(int i=0; i<=N; i++)
		{
			og[i]=new ArrayList<Integer>();			
			g[i]=new ArrayList<Integer>();
		}
	}

	static  long pow(long a,long b)
	{
		long mod=1000000007;
		long pow=1;
		long x=a;
		while(b!=0)
		{
			if((b&1)!=0)pow=(pow*x)%mod;
			x=(x*x)%mod;
			b/=2;
		}
		return pow;
	}
	static long toggleBits(long x)//one's complement || Toggle bits
	{
		int n=(int)(Math.floor(Math.log(x)/Math.log(2)))+1;

		return ((1<<n)-1)^x;
	}
	static int countBits(long a)
	{
		return (int)(Math.log(a)/Math.log(2)+1);
	}
	static void sort(int[] a) {
		ArrayList<Integer> l=new ArrayList<>();
		for (int i:a) l.add(i);
		Collections.sort(l);
		for (int i=0; i<a.length; i++) a[i]=l.get(i);
	}
	static boolean isPrime(long N)
	{
		if (N<=1)  return false; 
		if (N<=3)  return true; 
		if (N%2 == 0 || N%3 == 0) return false; 
		for (int i=5; i*i<=N; i=i+6) 
			if (N%i == 0 || N%(i+2) == 0) 
				return false; 
		return true; 
	}
	static long GCD(long a,long b) 
	{
		if(b==0)
		{
			return a;
		}
		else return GCD(b,a%b );
	}

	//Debugging Functions Starts

	static void print(char A[])
	{
		for(char c:A)System.out.print(c+" ");
		System.out.println();
	}
	static void print(boolean A[])
	{
		for(boolean c:A)System.out.print(c+" ");
		System.out.println();
	}
	static void print(int A[])
	{
		for(int a:A)System.out.print(a+" ");
		System.out.println();	
	}
	static void print(long A[])
	{
		for(long i:A)System.out.print(i+ " ");
		System.out.println();

	}
	static void print(ArrayList<Integer> A)
	{
		for(int a:A)System.out.print(a+" ");
		System.out.println();
	}

	//Debugging Functions END
	//----------------------
	//IO FUNCTIONS STARTS
	static HashMap<Integer,Integer> Hash(int A[])
	{
		HashMap<Integer,Integer> mp=new HashMap<>();
		for(int a:A)
		{
			int f=mp.getOrDefault(a,0)+1;
			mp.put(a, f);
		}
		return mp;
	}
	static int i()
	{
		return in.nextInt();
	}

	static long l()
	{
		return in.nextLong();
	}

	static int[] input(int N){
		int A[]=new int[N];
		for(int i=0; i<N; i++)
		{
			A[i]=in.nextInt();
		}
		return A;
	}

	static long[] inputLong(int N)     {
		long A[]=new long[N];
		for(int i=0; i<A.length; i++)A[i]=in.nextLong();
		return A;
	}

	//IO FUNCTIONS END

}

class node 
{
	int min,i,last;
	StringBuilder sb;
	node(int x)
	{
		sb=new StringBuilder();
		min=x;
	}
	node(int x,int a,int b)
	{		
		this.min=x;
		i=a;
		last=b;
	}

}

//Code For FastReader
//Code For FastReader
//Code For FastReader
//Code For FastReader
class FastReader
{
	BufferedReader br;
	StringTokenizer st;
	public FastReader()
	{
		br=new BufferedReader(new InputStreamReader(System.in));
	}

	String next()
	{
		while(st==null || !st.hasMoreElements())
		{
			try
			{
				st=new StringTokenizer(br.readLine());
			}
			catch(IOException e)
			{
				e.printStackTrace();
			}
		}
		return st.nextToken();
	}

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

	long nextLong()
	{
		return Long.parseLong(next());
	}
	//gey
	double nextDouble()
	{
		return Double.parseDouble(next());
	}

	String nextLine()
	{
		String str="";
		try
		{
			str=br.readLine();
		}
		catch (IOException e)
		{
			e.printStackTrace();
		}
		return str;
	}

}