#include <stdio.h> #include <bits/stdc++.h> #include <atcoder/all> using namespace atcoder; using mint = modint998244353; using namespace std; #define rep(i,n) for (int i = 0; i < (n); ++i) #define Inf32 1000000001 #define Inf64 1000000000000000001 int main(){ int n; cin>>n; int l = 0,r = n+1; int x = 0,y = n; rep(i,10){ if(l+1==r){ cout<<"? 1"<<endl; continue; } int mid = (l+r)/2; cout<<"? "<<mid<<endl; int ret; cin>>ret; if(mid-l>ret-x){ r = mid; y = ret; } else{ l = mid; x = ret; } //cout<<l<<' '<<r<<' '<<x<<' '<<y<<endl; } cout<<"Yes "<<l<<' '<<r<<endl; return 0; }