#include <bits/stdc++.h>
const int mod = 1e6 + 3;
int add(int a, int b) { return (a += b) >= mod ? a -= mod : a; }
int sub(int a, int b) { return add(a, mod - b); }
int mul(int a, int b) { return int(1LL * a * b % mod); }
int pow(int a, int64_t n) {
  int res = 1;
  while (n > 0) {
    if (n & 1) {
      res = mul(res, a);
    }
    a = mul(a, a);
    n >>= 1;
  }
  return res;
}
int inv(int a) { return pow(a, mod - 2); }
int main() {
  const int n = 11;
  std::vector<int> f(n + 1);
  for (int i = 1; i <= n; ++i) {
    std::cout << "? " << i << std::endl;
    std::cin >> f[i];
    if (f[i] == 0) {
      std::cout << "! " << i << std::endl;
      return 0;
    }
  }
  std::vector<std::vector<int> > a(1 + n, std::vector<int>(1 + n));
  for (int i = 1; i <= n; ++i) {
    for (int j = 1; j <= n; ++j) {
      a[i][j] = pow(i, j - 1);
    }
  }
  for (int j = 1, i = 1; j <= n; ++j) {
    bool was = false;
    for (int k = i; k <= n; ++k) {
      if (a[k][j] != 0) {
        was = true;
        std::swap(a[i], a[k]);
        std::swap(f[i], f[k]);
        break;
      }
    }
    if (!was) {
      continue;
    }
    for (int k = i + 1; k <= n; ++k) {
      int coeff = mul(sub(0, inv(a[k][j])), a[i][j]);
      for (int t = j; t <= n; ++t) {
        a[k][t] = add(mul(coeff, a[k][t]), a[i][t]);
      }
      assert(a[k][j] == 0);
      f[k] = add(f[i], mul(coeff, f[k]));
    }
    i++;
  }
  std::vector<int> x(1 + n);
  for (int i = n; i >= 1; --i) {
    assert(a[i][i] != 0);
    int res = f[i];
    for (int j = i + 1; j <= n; ++j) {
      res = sub(res, mul(a[i][j], x[j]));
    }
    x[i] = mul(res, inv(a[i][i]));
  }
  for (int i = 0; i < mod; ++i) {
    int p = 1, s = 0;
    for (int j = 1; j <= n; ++j) {
      s = add(s, mul(x[j], p));
      p = mul(p, i);
    }
    if (s == 0) {
      std::cout << "? " << i << std::endl;
      int v;
      std::cin >> v;
      assert(v == 0);
      std::cout << "! " << i << std::endl;
      return 0;
    }
  }
  std::cout << "! " << -1 << std::endl;
  return 0;
}
