#include <bits/stdc++.h>
#include <unistd.h>
#include <sys/time.h>
#include <stdlib.h>

using namespace std;

// using mint = long double;
// using mint = modint998244353;
// using mint = modint1000000007;

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<P, ll> T;
typedef pair<ll, vector<ll>> Pd;

const ll INF = 1e18;
const ll fact_table = 3200008;

priority_queue <ll> pql;
priority_queue <P> pqp;
//big priority queue
// priority_queue <ll, vector<ll>, greater<ll> > pqls;
// priority_queue <P, vector<P>, greater<P> > pqps;
//small priority queue
//top pop

ll dx[8] = {1, 0, -1, 0, 1, 1, -1, -1};
ll dy[8] = {0, 1, 0, -1, -1, 1, 1, -1};
//↓,→,↑,←

/*
#define endl "\n"
#ifdef ENJAPMA
#undef endl
#endif
*/

#define p(x) cout<<x<<endl;
#define el cout<<endl;
#define pe(x) cout<<x<<" ";
#define ps(x) cout<<fixed<<setprecision(25)<<x<<endl;
#define pu(x) cout<<(x);
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define pc(x) cout << x << ",";
#define rep(i, n) for (ll i = 0; i < (n); i ++)
#define rep2(i, a, b) for (ll i = a; i <= (b); i++)
#define rep3(i, a, b) for (ll i = a; i >= (b); i--)

typedef vector<ll> vec;
typedef vector<vector<ll>> mat;

// const ll mod = 998244353ll;
const ll mod = 1000000007ll;

ll mypow(ll a, ll b, ll m = mod) {ll x = 1; while (b) {while (!(b & 1)) {(a *= a) %= m; b >>= 1;}(x *= a) %= m; b--;} return x;}
vec readvec(ll read) { vec res(read); for (int i = 0; i < read; i++) { cin >> res[i]; } return res;}
void YES(bool cond) { if (cond) { p("YES");} else { p("NO");} return;}
void Yes(bool cond) { if (cond) { p("Yes");} else { p("No");} return;}
void line() { p("--------------------"); return;}

/*
ll fact[fact_table + 5], rfact[fact_table + 5];

void c3_init() {
    fact[0] = rfact[0] = 1;
    for (ll i = 1; i <= fact_table; i++) {
        fact[i] = (fact[i - 1] * i) % mod;
    }
    rfact[fact_table] = mypow(fact[fact_table], mod - 2, mod);
    for (ll i = fact_table; i >= 1; i--) {
        rfact[i - 1] = rfact[i] * i;
        rfact[i - 1] %= mod;
    }
    return;
}
ll c3(ll n, ll r) {
    return (((fact[n] * rfact[r]) % mod ) * rfact[n - r]) % mod;
}
*/

bool icpc = false;
bool multicase = false;

ll n, k;
ll h, w;
ll inpo;

ll x[500005], y[500005];

vec primes;
bool ok = false;

ll query(ll pos) {
    pe("?"); p(pos + 1);
    
    int ans;
    cin >> ans;
    /*
    int res = x[pos];
    p(res);
    for (int j=0;j<n;j++) {
        if (j == inpo) {
            y[(j + 1) % n] += (x[j]);
        } else {
            y[(j + n - 1) % n] += x[j] / 2;
            y[(j + 1) % n] += (x[j] + 1) / 2;
        }
    }
    for (int j = 0; j < n; j++) {
        x[j] = y[j];
        y[j] = 0;
        pe(x[j]);
    }
    el;
    */
    return ans;
}

void answer(ll pos) {
    pe("!"); p(pos + 1);
    return;
}


void init() {
    struct timeval _time;
    gettimeofday(&_time, NULL);
    ll usec = _time.tv_usec * 1000000;
    srand(usec);
    return;
}

bool solve() {
    cin >> n >> k;
    for (int i = 0; i < n; i++) {
        x[i] = k;
    }
    ll l = 0, r = n - 1;
    bool find = false;
    query(0);
    for (int turn = 1; turn <= 999; turn++) {
        // [l, r] の中にいることが確定
        ll haba = turn;
        if (n % 2 == 0) {
            haba = min(haba, (n - 2) / 2);
        } else {
            haba = min(haba, (n - 1) / 2);
        }
        if (!find) {
            // まだ見つけてない
            int ans = query((l + n - 1) % n);
            if (ans != k) {
                find = true;
                if (ans > k) {
                    r = (l + n - 1) % n;
                    l = (l + n - 1 + n - haba) % n;
                    continue;
                } else {
                    r = (l + haba) % n;
                    l = (l) % n;
                    continue;
                }
            } else {
                l += haba;
            }
        } else {
            if ((r + n - 1) % n == l) {
                answer(l);
                break;
            }
            int mid = -1;
            if (r > l) {
                mid = (r + l) / 2;
            } else {
                mid = (r + l + n) / 2;
                mid %= n;
            }
            int q = mid + (n - 1) + n - haba;
            q %= n;
            int ans = query(q);

            if (ans != k) {
                r = mid;
            } else if (haba * 2 + 2 == n) {
                int ans = query(q + 1);
                if (ans < k) {
                    answer((q + n / 2) % n);
                } else {
                    answer(q);
                }
                break;
            } else {
                l = mid;
            }
        }
    }
    return true;
}

int main() {

    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    for (ll i = 2; i <= 1000; i++) {
        bool prime = true;
        for (ll j = 2; j * j <= i; j++) {
            if (i % j == 0) prime = false;
        }
        if (prime) primes.pb(i);
    }

    if (icpc) {
        while (solve());
        return 0;
    }
    ll q, testcase = 1;
    if (multicase) {
        cin >> q;
    } else {
        q = 1;
    }
    while (q--) {
        // pu("Case ");pu("#");pu(testcase);pu(": ");
        solve();
        testcase++;
    }

// solve();
    return 0;
}