#include <bits/stdc++.h>
using namespace std;
const int P = 1000003;
int a[15][15];
int qp(int x, int y) {
  int z = 1;
  for (; y; y >>= 1, x = 1LL * x * x % P) {
    if (y & 1) z = 1LL * z * x % P;
  }
  return z;
}
int ask(int x) {
  printf("? %d\n", x), fflush(stdout);
  int y;
  scanf("%d", &y);
  return y;
}
void gauss() {
  int n = 10;
  for (int i = 0; i <= n; i++) {
    for (int j = i; j <= n; j++) {
      if (fabs(a[j][i]) > 1e-8) {
        for (int k = 0; k <= n + 1; k++) {
          swap(a[i][k], a[j][k]);
        }
        break;
      }
    }
    for (int j = 0; j <= n; j++)
      if (i ^ j) {
        int r = 1LL * a[j][i] * qp(a[i][i], P - 2) % P;
        for (int k = i; k <= n + 1; k++) {
          a[j][k] = (a[j][k] - 1LL * a[i][k] * r) % P;
        }
      }
  }
  for (int i = 0; i <= n; i++) {
    a[i][i] = 1LL * a[i][n + 1] * qp(a[i][i], P - 2) % P;
  }
}
int main() {
  for (int i = 0; i <= 10; i++) {
    if (!(a[i][11] = ask(i))) printf("! %d\n", i), exit(0);
    for (int j = 0; j <= 10; j++) a[i][j] = qp(i, j);
  }
  gauss();
  for (int i = 0; i < P; i++) {
    int s = 0;
    for (int j = 0; j <= 10; j++) {
      s = (s + 1LL * qp(i, j) * a[j][j]) % P;
    }
    if (!s) printf("! %d\n", i), exit(0);
  }
  printf("! -1\n");
  return 0;
}
