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.*;


public class Main implements Runnable {
    int n, m, k;
    static boolean use_n_tests = false;


    void solve(FastScanner in, PrintWriter out, int testNumber) {
        n = in.nextInt();
        int steps = 100;
        if (n <= steps) {
            int[] a = new int[n];
            for (int i = 0; i < n; i++) {
                a[i] = ask(i);
            }
            for (int i = 0; i < n; i++) {
                int leftv = Integer.MAX_VALUE;
                if (i > 0) {
                    leftv = a[i - 1];
                }
                int right = Integer.MAX_VALUE;
                if (i + 1 < n) {
                    right = a[i + 1];
                }
                if (leftv > a[i] && right > a[i]) {
                    out.println("! " + (i + 1));
                    break;
                }
            }
        } else {
            int f = ask(0);
            int n1 = ask(1);
            if (f < n1) {
                out.println("! 1");
                return;
            }
            int ls = ask(n - 1);
            int en = ask(n - 2);
            if (en > ls) {
                out.println("! " + n);
                return;
            }
            int l = 0;
            int r = n - 1;
            while (r - l >= 2) {
                int m = (l + r) / 2;
                if (r - l == 2) {
                    out.println("! " + (m + 1));
                    return;
                }
                int mid =  ask(m);
                int mid1 = ask(m + 1);
                if (mid < mid1) {
                    r = m + 1;
                } else {
                    l = m;
                }
            }
            if (l == r || ask(l) < ask(r)) {
                out.println("! " + (l + 1));
            } else {
                out.println("! " + (r + 1));
            }
            System.out.flush();
            out.flush();
        }

    }

    int ask(int i) {
        System.out.println("? " + (i + 1));
        System.out.flush();
        return in.nextInt();
    }

    class Ms {
        int a, b;
        long minus;

        public long getMinus() {
            return minus;
        }
    }

    // ****************************** template code ***********
    static int stack_size = 1 << 27;

    void pre_solve() {
    }

    class Coeff {
        long mod;
        long[][] C;
        long[] fact;
        boolean cycleWay = false;

        Coeff(int n, long mod) {
            this.mod = mod;
            fact = new long[n + 1];
            fact[0] = 1;
            for (int i = 1; i <= n; i++) {
                fact[i] = i;
                fact[i] %= mod;
                fact[i] *= fact[i - 1];
                fact[i] %= mod;
            }
        }

        Coeff(int n, int m, long mod) {
            // n > m
            cycleWay = true;
            this.mod = mod;
            C = new long[n + 1][m + 1];
            for (int i = 0; i <= n; i++) {
                for (int j = 0; j <= Math.min(i, m); j++) {
                    if (j == 0 || j == i) {
                        C[i][j] = 1;
                    } else {
                        C[i][j] = C[i - 1][j - 1] + C[i - 1][j];
                        C[i][j] %= mod;
                    }
                }
            }
        }

        public long C(int n, int m) {
            if (cycleWay) {
                return C[n][m];
            }
            return fC(n, m);
        }

        private long fC(int n, int m) {
            return (fact[n] * inv(fact[n - m] * fact[m] % mod)) % mod;
        }

        private long inv(long r) {
            if (r == 1)
                return 1;
            return ((mod - mod / r) * inv(mod % r)) % mod;
        }
    }

    class Pair {
        int first;
        int second;

        public int getFirst() {
            return first;
        }

        public int getSecond() {
            return second;
        }
    }

    class MultisetTree<T> {
        int size = 0;

        TreeMap<T, Integer> mp = new TreeMap<>();

        void add(T x) {
            mp.merge(x, 1, Integer::sum);
            size++;
        }

        void remove(T x) {
            if (mp.containsKey(x)) {
                mp.merge(x, -1, Integer::sum);
                if (mp.get(x) == 0) {
                    mp.remove(x);
                }
                size--;
            }
        }

        boolean contains(T x) {
            return mp.containsKey(x);
        }

        T greatest() {
            return mp.lastKey();
        }

        T smallest() {
            return mp.firstKey();
        }

        int size() {
            return size;
        }

        int diffSize() {
            return mp.size();
        }

        void clear() {
            mp.clear();
            size = 0;
        }
    }

    class Multiset<T> {
        int size = 0;

        Map<T, Integer> mp = new HashMap<>();

        void add(T x) {
            mp.merge(x, 1, Integer::sum);
            size++;
        }

        boolean contains(T x) {
            return mp.containsKey(x);
        }

        void remove(T x) {
            if (mp.containsKey(x)) {
                mp.merge(x, -1, Integer::sum);
                if (mp.get(x) == 0) {
                    mp.remove(x);
                }
                size--;
            }
        }

        int size() {
            return size;
        }

        int diffSize() {
            return mp.size();
        }
    }

    static class Range {
        int l, r;
        int id;

        public int getL() {
            return l;
        }

        public int getR() {
            return r;
        }

        public Range(int l, int r, int id) {
            this.l = l;
            this.r = r;
            this.id = id;
        }
    }

    static class Array {
        static Range[] readRanges(int n, FastScanner in) {
            Range[] result = new Range[n];
            for (int i = 0; i < n; i++) {
                result[i] = new Range(in.nextInt(), in.nextInt(), i);
            }
            return result;
        }

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

        static public <T> long sum(T[] a) {
            long sum = 0;
            for (T x : a) {
                if (x instanceof Integer) {
                    sum += (Integer) x;
                } else {
                    sum += (Long) x;
                }
            }
            return sum;
        }

        static public int min(Integer[] a) {
            int mn = Integer.MAX_VALUE;
            for (int x : a) {
                mn = Math.min(mn, x);
            }
            return mn;
        }

        static public int min(int[] a) {
            int mn = Integer.MAX_VALUE;
            for (int x : a) {
                mn = Math.min(mn, x);
            }
            return mn;
        }

        static public int max(Integer[] a) {
            int mx = Integer.MIN_VALUE;
            for (int x : a) {
                mx = Math.max(mx, x);
            }
            return mx;
        }

        static public int max(int[] a) {
            int mx = Integer.MIN_VALUE;
            for (int x : a) {
                mx = Math.max(mx, x);
            }
            return mx;
        }

        static public int[] readint(int n, FastScanner in) {
            int[] out = new int[n];
            for (int i = 0; i < out.length; i++) {
                out[i] = in.nextInt();
            }
            return out;
        }
    }

    class Graph {
        List<List<Integer>> graph;

        Graph(int n) {
            create(n);
        }

        void create(int n) {
            List<List<Integer>> graph = new ArrayList<>();
            for (int i = 0; i < n; i++) {
                graph.add(new ArrayList<>());
            }
            this.graph = graph;
        }

        void readBi(int m, FastScanner in) {
            for (int i = 0; i < m; i++) {
                int v = in.nextInt() - 1;
                int u = in.nextInt() - 1;
                graph.get(v).add(u);
                graph.get(u).add(v);
            }
        }
    }

    class FastScanner {
        BufferedReader br;
        StringTokenizer st;

        public FastScanner(InputStream io) {
            br = new BufferedReader(new InputStreamReader(io));
        }

        public String line() {
            String result = "";
            try {
                result = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return result;
        }

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

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

        public int[] nextArray(int n) {
            int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = in.nextInt();
            }
            return res;
        }

        public long[] nextArrayL(int n) {
            long[] res = new long[n];
            for (int i = 0; i < n; i++) {
                res[i] = in.nextLong();
            }
            return res;
        }

        public Long[] nextArrayL2(int n) {
            Long[] res = new Long[n];
            for (int i = 0; i < n; i++) {
                res[i] = in.nextLong();
            }
            return res;
        }


        public Integer[] nextArray2(int n) {
            Integer[] res = new Integer[n];
            for (int i = 0; i < n; i++) {
                res[i] = in.nextInt();
            }
            return res;
        }

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

    }

    void run_t_tests() {
        pre_solve();
        int t = in.nextInt();
        int i = 0;
        while (t-- > 0) {
            solve(in, out, i++);
        }
    }

    void run_one() {
        solve(in, out, -1);
    }

    @Override
    public void run() {
        in = new FastScanner(System.in);
        out = new PrintWriter(System.out);
        if (use_n_tests) {
            run_t_tests();
        } else {
            run_one();
        }
        out.close();
    }

    static FastScanner in;
    static PrintWriter out;

    public static void main(String[] args) throws InterruptedException {
        Thread thread = new Thread(null, new Main(), "", stack_size);
        thread.start();
        thread.join();
    }
}