Problem: This is an interactive problem.

Homer likes arrays a lot and he wants to play a game with you. 

Homer has hidden from you a permutation a_1, a_2, ..., a_n of integers 1 to n. You are asked to find any index k (1 ≤ k ≤ n) which is a local minimum. 

For an array a_1, a_2, ..., a_n, an index i (1 ≤ i ≤ n) is said to be a local minimum if a_i < min\\{a_{i-1},a_{i+1}\}, where a_0 = a_{n+1} = +∞. An array is said to be a permutation of integers 1 to n, if it contains all integers from 1 to n exactly once.

Initially, you are only given the value of n without any other information about this permutation.

At each interactive step, you are allowed to choose any i (1 ≤ i ≤ n) and make a query with it. As a response, you will be given the value of a_i. 

You are asked to find any index k which is a local minimum after at most 100 queries.

Interaction

You begin the interaction by reading an integer n (1≤ n ≤ 10^5) on a separate line.

To make a query on index i (1 ≤ i ≤ n), you should output "? i" in a separate line. Then read the value of a_i in a separate line. The number of the "?" queries is limited within 100.

When you find an index k (1 ≤ k ≤ n) which is a local minimum, output "! k" in a separate line and terminate your program. 

In case your query format is invalid, or you have made more than 100 "?" queries, you will receive Wrong Answer verdict. 

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.



Hack Format

The first line of the hack should contain a single integer n (1 ≤ n ≤ 10^5).

The second line should contain n distinct integers a_1, a_2, ..., a_n (1 ≤ a_i ≤ n).

Example

Input


5
3
2
1
4
5


Output


? 1
? 2
? 3
? 4
? 5
! 3

Note

In the example, the first line contains an integer 5 indicating that the length of the array is n = 5.

The example makes five "?" queries, after which we conclude that the array is a = [3,2,1,4,5] and k = 3 is local minimum.

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;
import java.math.*;
import java.math.BigInteger;


public final class A
{    
	static StringBuilder ans=new StringBuilder();
	static FastReader in=new FastReader();
	static ArrayList<ArrayList<Integer>> g,tg;
	static long mod=998244353;
	static boolean set[],col[]; 
	static int par[];
	static pair size[],size1[];
	static char G[][];
	static int dp[][];
	//static Pair moves[]= {new Pair(-1,0),new Pair(1,0), new Pair(0,-1), new Pair(0,1)};
	public static void main(String args[])throws IOException
	{		
		//System.out.println("YES");
		int N=i();
		int index=0;
		int A[]=new int[N+2];
		set=new boolean[N+2];
		A[0]=1000000;A[N+1]=1000000;
		set[0]=true;
		set[N+1]=true;
		int l=1,r=N;
		while(l<=r)
		{
			int m=l+(r-l)/2;
			for(int i=m-1; i<=m+1; i++)
			{
				if(!set[i])
				{
					set[i]=true;
					A[i]=ask(i);
				}
			}
			if(A[m]<A[m-1] && A[m]<A[m+1])
			{
				index=m;
				break;
			}
			else if(A[m-1]<A[m])
			{
				r=m-1;
			}
			else
			{
				l=m+1;
			}
		}
		System.out.println("! "+index);
	}
	static int ask(int N)
	{
		System.out.println("? "+N);
		return i();
	}
	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 long mul(long a, long b)
	{
		return ( a %mod * 1L * b%mod )%mod;
	}
	static void swap(int A[],int a,int b)
	{
		int t=A[a];
		A[a]=A[b];
		A[b]=t;
	}


	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);
		int t=Math.min(a, b);
		b=Math.max(a, b);
		a=t;
		if(a!=b)
		{
			g.get(a).add(b);
			g.get(b).add(a);
			par[a]+=par[b];
			par[b]=a;
		}
	}
	static boolean isSorted(int A[])
	{
		for(int i=1; i<A.length; i++)
		{
			if(A[i]<A[i-1])return false;
		}
		return true;
	}

	static boolean isDivisible(StringBuilder X,int i,long num)
	{
		long r=0;
		for(; i<X.length(); i++)
		{
			r=r*10+(X.charAt(i)-'0');
			r=r%num;
		}
		return r==0;
	}    



	static int lower_Bound(int A[],int low,int high, int x) 
	{ 
		if (low > high) 
			if (x >= A[high]) 
				return A[high]; 

		int mid = (low + high) / 2; 

		if (A[mid] == x) 
			return A[mid]; 

		if (mid > 0 && A[mid - 1] <= x && x < A[mid]) 
			return A[mid - 1]; 

		if (x < A[mid]) 
			return lower_Bound( A, low, mid - 1, x); 

		return lower_Bound(A, mid + 1, high, x); 
	} 

	static String f(String A)
	{
		String X="";
		for(int i=A.length()-1; i>=0; i--)
		{
			int c=A.charAt(i)-'0';
			X+=(c+1)%2;
		}
		return X;
	}

	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 String swap(String X,int i,int j)
	{
		char ch[]=X.toCharArray();
		char a=ch[i];
		ch[i]=ch[j];
		ch[j]=a;
		return new String(ch);
	}

	static int sD(long n)  
	{  

		if (n % 2 == 0 )  
			return 2;  

		for (int i = 3; i * i <= n; i += 2) {  
			if (n % i == 0 )  
				return i;  
		}  

		return (int)n;  
	}  

	static void setGraph(int N)
	{
		set=new boolean[N+1];
		col=new boolean[N+1];
		size=new pair[N+1];
		size1=new pair[N+1];
		g=new ArrayList<ArrayList<Integer>>();
		tg=new ArrayList<ArrayList<Integer>>();
		for(int i=0; i<=N; i++)
		{
			size[i]=new pair();
			size1[i]=new pair();
			g.add(new ArrayList<Integer>());
			tg.add(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 long fact(long N)
	{ 
		long n=2; 
		if(N<=1)return 1;
		else
		{
			for(int i=3; i<=N; i++)n=(n*i)%mod;
		}
		return n;
	}

	static int kadane(int A[])
	{
		int lsum=A[0],gsum=A[0];
		for(int i=1; i<A.length; i++)
		{
			lsum=Math.max(lsum+A[i],A[i]);
			gsum=Math.max(gsum,lsum);
		}
		return gsum;
	}

	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 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();
	}

	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;
	}

	static long GCD(long a,long b) 
	{
		if(b==0)
		{
			return a;
		}
		else return GCD(b,a%b );
	}

}

class pair implements Comparable<pair>
{
	long health,power;
	pair()
	{
		health=0;
		power=0;
	}
	pair(long h,long p)
	{
		health=h;
		power=p;
	}
	public int compareTo(pair X)
	{
		if(this.power>X.power)return 1;
		else if(this.power==X.power)return 0;
		else return -1;
	}
}

//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());
	}

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

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

}