#include <bits/stdc++.h>
using namespace std;
constexpr int maxn = 64, mod = 1e6 + 3, qtot = 50;
constexpr inline int add(const int a, const int b) { return (a + b) % mod; }
constexpr inline int mul(const int a, const int b) {
  return (1ll * a * b) % mod;
}
constexpr inline int sub(const int a, const int b) {
  return (a - b + mod) % mod;
}
inline int qpow(int base, int b) {
  int res = 1;
  while (b) {
    if (b & 1) res = mul(res, base);
    base = mul(base, base);
    b >>= 1;
  }
  return res;
}
inline int inv(const int x) { return qpow(x, mod - 2); }
inline int calc(const int a, const int b) { return mul(a, inv(b)); }
mt19937 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
int ques[maxn], mat[maxn][maxn], a[maxn];
inline int query(const int x) {
  int res;
  printf("? %d\n", x);
  fflush(stdout);
  scanf("%d", &res);
  return res;
}
int mem[maxn][maxn];
inline void query() {
  for (int k = 0; k < qtot; k++) {
    const int x = ques[k];
    mat[k][11] = query(x);
    for (int i = 0; i <= 10; i++) mat[k][i] = qpow(x, i);
  }
}
inline void gauss() {
  const int n = qtot - 1;
  const int m = 10;
  for (int i = 0; i <= m; i++) {
    int r = -1;
    for (int j = i; j <= n; j++)
      if (mat[j][i]) r = j;
    if (r == -1) exit(-1);
    swap(mat[i], mat[r]);
    for (int j = i + 1; j <= n; j++) {
      const int k = calc(mat[j][i], mat[i][i]);
      for (int l = i; l <= m + 1; l++)
        mat[j][l] = sub(mat[j][l], mul(mat[i][l], k));
    }
  }
  for (int i = m; i >= 0; i--) {
    a[i] = mat[i][m + 1];
    for (int l = i + 1; l <= m; l++) a[i] = sub(a[i], mul(mat[i][l], a[l]));
    a[i] = calc(a[i], mat[i][i]);
  }
}
inline int calc(int x) {
  int res = 0;
  for (int i = 0; i <= 10; i++) res = add(res, mul(a[i], qpow(x, i)));
  return res;
}
inline void solve() {
  for (int i = 0; i < mod; i++)
    if (!calc(i)) {
      printf("! %d\n", i);
      return;
    }
  puts("! -1");
}
int main() {
  for (int i = 0; i < qtot; i++) ques[i] = rnd() % mod;
  query();
  gauss();
  solve();
  return 0;
}
