//interactive
ll@(t,x0,y0,x1,y1);
ll a=0,b=t;
while(a+1<b){
	ll m=a+b>>1;
	wt("?",m);
	ll@x,@y;
	if(abs(x-x0)+abs(y-y0)>abs(x-x1)+abs(y-y1)){
		b=m;
	}else{
		a=m;
	}
}
wt("!",a);