main(){
	int n;
	scanf("%d",&n);
	if(fork()){
		int a=0;
		for(int i=n;i-=2,i>=0;){
			int z=0;
			scanf("%d",&z);
			if(z==i){
				a=i+1;
			}
			if(z==i+1){
				a=i;
			}
		}
		wait(0);
		printf("! %d\n",a);
	}else{
		for(int i=n;i-=2,i>=0;){
			printf("? %d %d\n",i,i+1);
		}
	}
}