#include <bits/stdc++.h>
using namespace std;
long long lgput(long long a, long long b, long long mod) {
  long long ret = 1;
  while (b) {
    if (b & 1) ret = (ret * a) % mod;
    a = (a * a) % mod;
    b >>= 1;
  }
  return (ret % mod);
}
inline long long inv(long long x, long long MOD) {
  return lgput(x, MOD - 2, MOD);
}
const long double PI = acos(-1);
const long double eps = 1e-6;
const long long mod = 1e6 + 3;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cout.precision(12);
  cout.fixed;
  int n = 11;
  vector<vector<long long> > gauss(n, vector<long long>(n + 1));
  vector<long long> sol(n);
  for (int i = 0; i < 11; ++i) {
    cout << "? " << i << '\n';
    cout.flush();
    gauss[i][0] = 1;
    cin >> gauss[i][n];
    for (int j = 1; j < n; ++j) gauss[i][j] = (gauss[i][j - 1] * i) % mod;
  }
  int i = 0;
  while (i < n) {
    for (int j = n; j >= i; --j) {
      gauss[i][j] = (gauss[i][j] * inv(gauss[i][i], mod)) % mod;
    }
    for (int k = i + 1; k < n; ++k) {
      for (int j = n; j >= i; --j) {
        gauss[k][j] =
            ((gauss[k][j] - (gauss[i][j] * gauss[k][i])) % mod + mod) % mod;
      }
    }
    ++i;
  }
  for (int i = n - 1; i >= 0; --i) {
    sol[i] = gauss[i][n];
    for (int j = n - 1; j > i; --j) {
      sol[i] = ((sol[i] - gauss[i][j] * sol[j]) % mod + mod) % mod;
    }
    sol[i] = sol[i] * inv(gauss[i][i], mod) % mod;
  }
  for (int x = 0; x < mod; ++x) {
    long long now = 1;
    long long sum = 0;
    for (int i = 0; i < n; ++i) {
      sum = (sum + sol[i] * now) % mod;
      now = (now * x) % mod;
    }
    if (sum == 0) {
      cout << "! " << x << '\n';
      cout.flush();
      return 0;
    }
  }
  cout << "! -1\n";
  cout.flush();
  return 0;
}
