#include using namespace std; int main(){ int n; cin>>n; auto query=[&](vector a,vector b){ int ka=a.size(),kb=b.size(); if (ka==0||kb==0) return 0; cout<<"? "<>r; assert(r!=-1); return r; }; vector> ans; for (int i=0;i b; for (int j=l;j1){ int mid=(l+r)/2; vector b; for (int j=i+1;j