#include <bits/stdc++.h>
using namespace std;
const int MOD = 1E6 + 3, K = 12;
long long inv[MOD];
vector<long long> ans(K, 0);
long long pw(int u, int p) {
  long long ret = 1;
  for (int i = 0; i < p; i++) (ret *= u) %= MOD;
  return ret;
}
struct TGauss {
  vector<long long> ve;
  int fi;
  TGauss(vector<long long> _ve = vector<long long>(K, 0)) {
    ve = _ve;
    fi = K;
    for (int i = 0; i < K; i++)
      if (ve[i] > 0) {
        fi = i;
        break;
      }
  }
  bool valid() { return fi < K; }
  TGauss operator^(const TGauss &oth) {
    TGauss ans = *this;
    if (ans.ve[oth.fi] > 0) {
      int pos = oth.fi;
      long long coe = ans.ve[pos] * inv[oth.ve[pos]] % MOD;
      for (int i = pos; i < K; i++) {
        (ans.ve[i] -= oth.ve[i] * coe) %= MOD;
        (ans.ve[i] += MOD) %= MOD;
      }
      ans.fi = K;
      for (int i = 0; i < K; i++)
        if (ans.ve[i] > 0) {
          ans.fi = i;
          break;
        }
    }
    return ans;
  }
  bool operator<(const TGauss &oth) const { return fi < oth.fi; }
};
vector<TGauss> ve;
TGauss ask(int u) {
  vector<long long> ve;
  for (int i = 0; i < K - 1; i++) ve.push_back(pw(u, i));
  ve.push_back(0);
  cout << "? " << u << endl;
  cin >> ve.back();
  return TGauss(ve);
}
int main() {
  inv[1] = 1;
  for (int i = 2; i < MOD; i++) inv[i] = MOD - MOD / i * inv[MOD % i] % MOD;
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  for (int i = 0; i <= K - 2; i++) {
    TGauss cur = ask(i);
    for (TGauss &v : ve) cur = cur ^ v;
    if (cur.valid()) {
      ve.push_back(cur);
      sort(ve.begin(), ve.end());
    } else
      break;
  }
  for (int i = K - 2; i >= 0; i--) {
    ans[i] = ve[i].ve.back();
    for (int j = i + 1; j <= K - 2; j++)
      (ans[i] -= ve[i].ve[j] * ans[j]) %= MOD;
    (ans[i] *= inv[ve[i].ve[i]]) %= MOD;
  }
  for (int i = 0; i < MOD; i++) {
    long long ret = 0;
    for (int j = 0; j <= K - 2; j++) (ret += ans[j] * pw(i, j)) %= MOD;
    if (ret == 0) {
      cout << "! " << i << endl;
      return 0;
    }
  }
  cout << "! -1" << endl;
  return 0;
}
