#include <bits/stdc++.h>
using namespace std;
using ll = int64_t;
using ull = uint64_t;
using ld = long double;
using uint = uint32_t;
const double EPS = 1e-8;
const int INF = 0x3F3F3F3F;
const ll LINF = 4611686018427387903;
const int MOD = 1e9 + 7;
const int mod = 1e6 + 3;
vector<vector<ll>> mat(11, vector<ll>(12));
ll mpow(ll a, int b) {
  ll res = 1;
  for (; b; b >>= 1, a = a * a % mod)
    if (b & 1) res = res * a % mod;
  return res;
}
signed main() {
  ios::sync_with_stdio(0);
  cin.tie(NULL);
  for (int i = 0; i < 11; i++) {
    cout << "? " << i + 1 << endl;
    int w;
    cin >> w;
    for (int j = 0; j <= 10; j++) mat[i][j] = mpow(i + 1, j);
    mat[i][11] = w;
  }
  for (int i = 0; i < 11; i++) {
    for (int j = i; j < 11; j++) {
      if (mat[j][i]) {
        swap(mat[j], mat[i]);
        break;
      }
    }
    for (int j = 0; j < 11; j++) {
      if (j == i || !mat[j][i]) continue;
      ll c = mat[i][i] * mpow(mat[j][i], mod - 2) % mod;
      for (int k = 0; k < 12; k++) mat[j][k] = mat[j][k] * c % mod;
      for (int k = 0; k < 12; k++)
        mat[j][k] = (mat[j][k] - mat[i][k] + mod) % mod;
    }
  }
  vector<ll> xx(11);
  for (int i = 0; i < 11; i++)
    xx[i] = mat[i][11] * mpow(mat[i][i], mod - 2) % mod;
  for (int i = 0; i < mod; i++) {
    ll res = 0;
    for (int j = 0; j < 11; j++) {
      res = (res + xx[j] * mpow(i, j)) % mod;
    }
    if (res == 0) {
      cout << "! " << i << '\n';
      return 0;
    }
  }
  cout << "! " << -1 << '\n';
}
