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:
//------------------>>>>>>>>>>>>>>>> HI . HOW ARE YOU? <<<<<<<<<<<<<<<<<<<<<<<<<<<<<------------------------------

import java.util.*;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.List;
import java.util.StringTokenizer;

//---------------------------->>>>>>>>>>>>>>>>>>>>>> FK OFF <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<-------------------

//--------------------------->>>>>>>>>>>>>>>>>>>>>>>> HACKER MF <<<<<<<<<<<<-------------------------------------

public class practice{
    static long[] count,count1,count2;
    static boolean[] prime;
    static boolean flag;
    static int[] spf;
    static Node[] nodes,nodes1,nodes2;
    static long[] arr;
    static long[][] cost;
    static int[] arrInt,darrInt,farrInt;
    static long[][] dp;
    static char[] ch,ch1,ch2;
    static long[] darr,farr;
    static int[][] mat,mat1;
    static boolean[] vis;
    static long x,h;
    static long maxl,sum,total;
    static double dec;
    static long mx = (long)1e7;
    static long inf = (long)1e18;
    static String s,s1,s2,s3,s4;
    static long minl;
    static long mod = (long)(1e9)+7;
    // static int minl = -1;
    // static long n;
    static int n,n1,n2,q,r1,c1,r2,c2;
    static int arr_size = (int)2e5+10;
    static long a;
    static long b;
    static long c;
    static long d;
    static long y,z;
    static int m;
    static long ans;
    static long k;
    static FastScanner sc;
    static String[] str,str1;
    static Set<Long> set,set1,set2;
    static SortedSet<Long> ss;
    static List<StringBuilder> list,list1,list2,list3;
    static PriorityQueue<Node> pq,pq1;
    static LinkedList<Node> ll,ll1,ll2;
    static Map<Integer,List<Integer>> map;
    static Map<Integer,Integer> map2;
    static Map<Integer,Long> mapL,mapR;
    static Map<Integer,Node> map1;
    static StringBuilder sb,sb1,sb2;
    static int index;
    static int[] dx = {0,-1,0,1,-1,1,-1,1};
    static int[] dy = {-1,0,1,0,-1,-1,1,1};

    static class Node{
        int first;
        int second;
        Node(int f,int s){
            this.first = f;
            this.second = s;
        }
    }

//     public static void solve(){
//
//        FastScanner sc = new FastScanner();
//        int t = sc.nextInt();
//        // int t = 1;
//        for(int tt = 1 ; tt <= t ; tt++){
//
////            int n = sc.nextInt();
////            arr = new long[n];
////
////            for(int i = 0 ; i < n ; i++){
////                arr[i] = sc.nextLong();
////            }
//
//            System.out.println("Case #"+tt+": "+cost);
//
//        }
//
//     }

    //--------------->>>>IF YOU ARE HERE FOR QUICKSORT HACK THEN SORRY NO HACK FOR YOU<<<------------------------------

    public static void solve(){

        int vertex = 1;
        boolean[] asked = new boolean[n+1];
        boolean[] connected = new boolean[n+1];
        int[][] adj = new int[n+1][n+1];

        while(true){

            int[] dist = ask(vertex);
            asked[vertex] = true;

            Node[] nodes = new Node[n];
            for(int i = 0 ; i < n ; i++){
                nodes[i] = new Node(dist[i],i+1);
            }

            Arrays.sort(nodes, new Comparator<Node>() {
                @Override
                public int compare(Node node, Node t1) {
                    return node.first - t1.first;
                }
            });

            int prev = vertex;
            int prevC = 1;
            boolean flag = false;
            int curr = -1;

            for(int i = 1 ; i < n ; ){

                int val = nodes[i].first;
                int c = 0;

                while(i < n && nodes[i].first == val){
                    if(connected[nodes[i].second]){
                        if(prevC == 1){
                            if(adj[nodes[i].second][prev] != 1)
                                adj[prev][nodes[i].second] = 1;
                        }
                        c += 1;
                        curr = nodes[i].second;
                    }
                    else{
                        if(prevC != 1){
                            if(!asked[nodes[i].second]) {
                                vertex = nodes[i].second;
                                flag = true;
                                break;
                            }
                        }
                        else{
                            if(adj[nodes[i].second][prev] != 1)
                                adj[prev][nodes[i].second] = 1;
                            connected[nodes[i].second] = true;
                            connected[prev] = true;
                            curr = nodes[i].second;
                            c += 1;
                        }
                    }
                    i += 1;
                }

                if(flag)
                    break;

                prev = curr;
                prevC = c;
                vertex = -1;
            }

            if(vertex == -1){
                break;
            }

        }

        sb.append("!").append("\n");

        for(int i = 1 ; i <= n ; i++){
            for(int j = 1 ; j <= n ; j++){
                if(adj[i][j] == 1)
                    sb.append(i + " " + j).append("\n");
            }
        }

    }

    private static int[] ask(int vertex) {

        System.out.println("? "+vertex);
        System.out.flush();

        int[] output = new int[n];
        for(int i = 0 ; i < n ; i++)
            output[i] = sc.nextInt();

        return output;

    }

    //----------->>>>>>> SPEED UP SPEED UP . THIS IS SPEEDFORCES . SPEED UP SPEEEEEEEEEEEEEEEEEEEEEEEEEEDDDDDD <<<<<<<------------------

    public static void main(String[] args) {

        sc = new FastScanner();
        // Scanner sc = new Scanner(System.in);
        sb = new StringBuilder();
//        int t = sc.nextInt();
        int t = 1;
        while(t > 0){

            // k = sc.nextLong();
            // x = sc.nextLong();
            // y = sc.nextLong();
            // z = sc.nextLong();

//             a = sc.nextLong();
//             b = sc.nextLong();
//             c = sc.nextLong();
//             d = sc.nextLong();

//             x = sc.nextLong();
//             y = sc.nextLong();
//             z = sc.nextLong();
            // d = sc.nextLong();

            n = sc.nextInt();

            // n1 = sc.nextInt();

//            m = sc.nextInt();
//             q = sc.nextInt();

//             a = sc.nextLong();
//             b = sc.nextLong();

//             k = sc.nextLong();

//            x = sc.nextLong();
            // d = sc.nextLong();

            // s = sc.next();

//            ch = sc.next().toCharArray();
            // ch1 = sc.next().toCharArray();

//             m = sc.nextInt();
            // n = 6;

//            arr = new long[n];
//            for(int i = 0 ; i < n ; i++){
//                arr[i] = sc.nextLong();
//            }

//            arrInt = new int[n];
//            for(int i = 0 ; i < n ; i++){
//                arrInt[i] = sc.nextInt();
//            }

            // x = sc.nextLong();
            // y = sc.nextLong();
//             ch = sc.next().toCharArray();
//            m = n;
////             m = sc.nextInt();
//            darr = new long[m];
//            for(int i = 0 ; i < m ; i++){
//                darr[i] = sc.nextLong();
//            }
            // k = sc.nextLong();
            // m = n;
//             darrInt = new int[n];
//             for(int i = 0 ; i < n ; i++){
//                 darrInt[i] = sc.nextInt();
//             }

            // farr = new long[m];
            // for(int i = 0 ; i < m ; i++){
            //     farr[i] = sc.nextLong();
            // }

            // farrInt = new int[m];
            // for(int i = 0; i < m ; i++){
            //     farrInt[i] = sc.nextInt();
            // }

            // m = n;
//            mat = new int[2][n];
//            for(int i = 0 ; i < 2 ; i++){
//                for(int j = 0 ; j < n ; j++){
//                    mat[i][j] = sc.nextInt();
//                }
//            }

//             m = n;
//             mat = new char[n][m];
//             for(int i = 0 ; i < n ; i++){
//                 String s = sc.next();
//                 for(int j = 0 ; j < m ; j++){
//                     mat[i][j] = s.charAt(j);
//                 }
//             }

            // str = new String[n];
            // for(int i = 0 ; i < n ; i++)
            //     str[i] = sc.next();

//             nodes = new Node[n];
//             for(int i = 0 ; i < n ;i++)
//                 nodes[i] = new Node(sc.nextLong(),(i));

            solve();
            t -= 1;
        }
        System.out.print(sb);

    }

    public static int log(double n,double base){

        if(n == 0 || n == 1)
            return 0;

        if(n == base)
            return 1;

        double num = Math.log(n);
        double den = Math.log(base);

        if(den == 0)
            return 0;

        return (int)(num/den);
    }

    public static boolean isPrime(long n) {
        // Corner cases
        if (n <= 1)
            return false;

        if (n <= 3)
            return true;

        // This is checked so that we can skip
        // middle five numbers in below loop
        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;
    }

    public static void SpecialSieve(int MAXN)
    {
        spf = new int[MAXN];
        spf[1] = 1;
        for (int i=2; i<MAXN; i++)

            // marking smallest prime factor for every
            // number to be itself.
            spf[i] = i;

        // separately marking spf for every even
        // number as 2
        for (int i=4; i<MAXN; i+=2)
            spf[i] = 2;

        for (int i=3; i*i<MAXN; i++)
        {
            // checking if i is prime
            if (spf[i] == i)
            {
                // marking SPF for all numbers divisible by i
                for (int j=i*i; j<MAXN; j+=i)

                    // marking spf[j] if it is not
                    // previously marked
                    if (spf[j]==j)
                        spf[j] = i;
            }
        }
    }

    public static ArrayList<Integer> getFactorization(int x)
    {
        ArrayList<Integer> ret = new ArrayList<Integer>();
        while (x != 1)
        {
            ret.add(spf[x]);
            x = x / spf[x];
        }
        return ret;
    }

    public static long gcd(long a, long b)
    {
        if (b == 0)
            return a;
        return gcd(b, a % b);
    }

    public static long lcm(long a, long b)
    {
        return (b/gcd(b, a % b)) * a;
    }

    public static long mod_inverse(long a,long mod){
        long x1=1,x2=0;
        long p=mod,q,t;
        while(a%p!=0){
            q = a/p;
            t = x1-q*x2;
            x1=x2; x2=t;
            t=a%p;
            a=p; p=t;
        }
        return x2<0 ? x2+mod : x2;
    }

    public static void swap(double[] curr,int i,int j){
        double temp = curr[j];
        curr[j] = curr[i];
        curr[i] = temp;
    }

    static final Random random=new Random();

    static void ruffleSortLong(long[] a) {
        int n=a.length;//shuffle, then sort
        for (int i=0; i<n; i++) {
            int oi=random.nextInt(n);
            long temp=a[oi];
            a[oi]=a[i]; a[i]=temp;
        }
        Arrays.sort(a);
    }

    static void ruffleSortInt(int[] a) {
        int n=a.length;//shuffle, then sort
        for (int i=0; i<n; i++) {
            int oi=random.nextInt(n);
            int temp=a[oi];
            a[oi]=a[i]; a[i]=temp;
        }
        Arrays.sort(a);
    }

    static void ruffleSortChar(char[] a) {
        int n=a.length;//shuffle, then sort
        for (int i=0; i<n; i++) {
            int oi=random.nextInt(n);
            char temp=a[oi];
            a[oi]=a[i]; a[i]=temp;
        }
        Arrays.sort(a);
    }

    static long binomialCoeff(long n, long k){

        long res = 1;

        // Since C(n, k) = C(n, n-k)
        if (k > n - k)
            k = n - k;

        // Calculate value of
        // [n * (n-1) *---* (n-k+1)] / [k * (k-1) *----* 1]
        for (long i = 0; i < k; ++i) {
            res = (res*(n - i));
            res = (res/(i + 1));
        }

        return res;
    }

    static long mod(long x)
    {
        long y = mod;
        long result = x % y;
        if (result < 0)
        {
            result += y;
        }
        return result;
    }

    static long[] fact;

    public static long inv(long n){
        return power(n, mod-2);
    }

    public static void fact(int n){
        fact = new long[n+1];
        fact[0] = 1;
        for(int j = 1;j<=n;j++)
            fact[j] = (fact[j-1]*(long)j)%mod;
    }

    public static long binom(int n, int k){

        long prod = fact[n];
        prod*=inv(fact[n-k]);
        prod%=mod;
        prod*=inv(fact[k]);
        prod%=mod;
        return prod;
    }

    static long power(long x, long y){
        if (y == 0)
            return 1;
        if (y%2 == 1)
            return (x*power(x, y-1))%mod;
        return power((x*x)%mod, y/2)%mod;
    }

    static void sieve(int n){

        prime = new boolean[n+1];
        for(int i=2;i<n;i++)
            prime[i] = true;

        for(int p = 2; p*p <=n; p++)
        {
            if(prime[p])
            {
                for(int i = p*p; i <= n; i += p)
                    prime[i] = false;
            }
        }

    }

    static long abs(long a){
        return Math.abs(a);
    }

    static int abs(int a){
        return Math.abs(a);
    }

    static int max(int a,int b){
        if(a>b)
            return a;
        else
            return b;
    }
    static double max(double a,double b){
        if(a>b)
            return a;
        else
            return b;
    }
    static double min(double a,double b){
        if(a>b)
            return b;
        else
            return a;
    }

    static int min(int a,int b){
        if(a>b)
            return b;
        else
            return a;
    }

    static long max(long a,long b){
        if(a>b)
            return a;
        else
            return b;
    }

    static long min(long a,long b){
        if(a>b)
            return b;
        else
            return a;
    }

    static long sq(long num){
        return num*num;
    }

    static double sq(double num){
        return num*num;
    }

    static long sqrt(long num){
        return (long)Math.sqrt(num);
    }

    static double sqrt(double num){
        return Math.sqrt(num);
    }

    static class FastScanner {

        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st=new StringTokenizer("");
        String next() {
            while (!st.hasMoreTokens())
                try {
                    st=new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }
//        void readArray(int n) {
//            arr = new long[n];
//            for (int i = 0; i < n; i++)
//                arr[i] = nextLong();
//        }
        long nextLong() {
            return Long.parseLong(next());
        }
    }

}