#include<stdio.h>

int main(void){

int low=1;
int high=1000000000;

while(low+1<high){
 int m=low*high;
 printf("? %d\n",m);
 int ans;
 scanf("%d",&ans);
 if(ans){
  low=m;
 } else {
  high=m;
 }
}
if(high==low){
printf("! %d\n",low);
return 0;
}
printf("? %d\n",high);
int ans;
scanf("%d",ans);
if(ans){
printf("!%d\n",high);
} else {
printf("%d\n",low);
}
return 0;
}