#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr ll mod = 1e6 + 3;
constexpr int k = 11;
ll powmod(ll a, ll b) {
  ll res = 1;
  while (b) {
    if (b & 1) {
      res = res * a % mod;
    }
    a = a * a % mod;
    b /= 2;
  }
  return res;
}
int ask(int x) {
  cout << "? " << x << endl;
  int res;
  cin >> res;
  if (res == -1) {
    exit(0);
  }
  if (res == 0) {
    cout << "! " << x << endl;
    exit(0);
  }
  return res;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  vector<vector<ll>> m(k, vector<ll>(k + 1, 1));
  for (int i = 0; i < k; ++i) {
    m[i][k] = ask(i);
    for (int j = 1; j < k; ++j) {
      m[i][j] = m[i][j - 1] * i % mod;
    }
  }
  vector<ll> polynomial(k);
  for (int row = 0; row < k; ++row) {
    int col = row;
    assert(m[row][col]);
    for (int row2 = 0; row2 < k; ++row2) {
      if (row == row2) {
        continue;
      }
      ll coef = m[row2][col] * powmod(m[row][col], mod - 2) % mod;
      if (!coef) {
        continue;
      }
      for (int c = col; c <= k; ++c) {
        m[row2][c] -= coef * m[row][c] % mod;
        if (m[row2][c] < 0) {
          m[row2][c] += mod;
        }
      }
    }
  }
  for (int i = 0; i < k; ++i) {
    polynomial[i] = m[i][k] * powmod(m[i][i], mod - 2) % mod;
  }
  reverse(polynomial.begin(), polynomial.end());
  auto f = [&](ll x) {
    ll cur = 0;
    for (ll a : polynomial) {
      cur = (cur * x + a) % mod;
    }
    return cur;
  };
  for (int i = 0; i < mod; ++i) {
    if (!f(i)) {
      cout << "! " << i << endl;
      return 0;
    }
  }
  cout << "! -1" << endl;
  return 0;
}
