#include <bits/stdc++.h>
using namespace std;
int t,n;
int query(int l,int r)
{
	if(l==r)return -1;
	printf("? %d %d\n",l,r);
	fflush(stdout);
	int x;scanf("%d",&x);
	return x;
}
int solve(int l,int r,int p)
{//printf("solve([%d,%d],%d)\n",l,r,p);
	if(l==r)return l;
	if(p==-1)p=query(l,r);
	if(r-l+1==2)return l^r^p;
	int m;
	int len=(r-l+1+1)/2;
	if(p<=l+len-1)m=l+len-1;
	else m=r-len;
	if(p<=m)
	{
		int tt=query(l,m);
		if(tt==p)return solve(l,m,tt);
		else return solve(m+1,r,-1);
	}
	else
	{
		int tt=query(m+1,r);
		if(tt==p)return solve(m+1,r,tt);
		else return solve(l,m,-1);
	}
}
int main()
{
	scanf("%d",&t);while(t--)
	{
		scanf("%d",&n);
		printf("! %d\n",solve(1,n,-1));fflush(stdout);
	}
	fclose(stdin);fclose(stdout);return 0;
}