#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e6 + 3;
const int MXROW = 1010;
const int MXCOL = 1010;
long long int a[MXROW][MXCOL];
inline long long int bigmod(long long int b, long long int p,
                            long long int MOD) {
  long long int res = 1 % MOD, x = b % MOD;
  while (p) {
    if (p & 1) res = (res * x) % MOD;
    x = (x * x) % MOD;
    p >>= 1;
  }
  return res % MOD;
}
inline int gaussian_elim(int n, int m, int MOD, vector<long long int> &res) {
  res.assign(m, 0);
  vector<long long int> pos(m, -1);
  int i, j, k, l, p, free_var = 0;
  long long int d;
  const long long MODSQ = 1LL * MOD * MOD;
  for (j = 0, i = 0; j < m && i < n; j++) {
    for (k = i, p = i; k < n; k++) {
      if (a[k][k] > a[p][j]) p = k;
    }
    if (a[p][j]) {
      pos[j] = i;
      for (l = j; l <= m; l++) swap(a[p][l], a[i][l]);
      d = bigmod(a[i][j], MOD - 2, MOD);
      for (k = 0; k < n && d; k++) {
        if (k != i && a[k][j]) {
          long long int x = (a[k][j] % MOD * d % MOD) % MOD;
          for (l = j; l <= m && x; l++) {
            if (a[i][l])
              a[k][l] = (MODSQ + a[k][l] - (a[i][l] % MOD * x % MOD)) % MOD;
          }
        }
      }
      i++;
    }
  }
  for (i = 0; i < m; i++) {
    if (pos[i] == -1)
      free_var++;
    else
      res[i] = (a[pos[i]][m] * bigmod(a[pos[i]][i], MOD - 2, MOD)) % MOD;
  }
  for (i = 0; i < n; i++) {
    long long int val = 0;
    for (j = 0; j < m; j++) val = (val + (res[j] * a[i][j])) % MOD;
    if (val != a[i][m]) return -1;
  }
  return free_var;
}
int main(int argc, char const *argv[]) {
  int n = 11, m = 11;
  for (int i = 0; i < n; i++) {
    long long int mul = 1;
    for (int j = 0; j < m; j++) {
      a[i][j] = mul;
      mul = (mul % MOD * i % MOD) % MOD;
    }
    cout << "? " << i << endl;
    long long int fx;
    cin >> fx;
    a[i][m] = fx;
  }
  vector<long long int> res;
  int free_var = gaussian_elim(n, m, MOD, res);
  assert(free_var == 0);
  for (int i = 0; i < MOD; i++) {
    long long int fx = 0, mul = 1;
    for (int j = 0; j < m; j++) {
      fx += (1LL * mul * res[j]) % MOD, fx %= MOD;
      mul = (1LL * mul * i) % MOD;
    }
    if (fx == 0) {
      cout << "! " << i << endl;
      return 0;
    }
  }
  cout << "! -1" << endl;
  return 0;
}
