#include <bits/stdc++.h>
#define whlie while
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define rep(i,N) for(int i = 0; i < (N); i++)
#define repr(i,N) for(int i = (N) - 1; i >= 0; i--)
#define rep1(i,N) for(int i = 1; i <= (N) ; i++)
#define repr1(i,N) for(int i = (N) ; i > 0 ; i--)
#define each(x,v) for(auto& x : v)
#define all(v) (v).begin(),(v).end()
#define sz(v) ((int)(v).size())
#define ini(...) int __VA_ARGS__; in(__VA_ARGS__)
#define inl(...) ll __VA_ARGS__; in(__VA_ARGS__)
#define ins(...) string __VA_ARGS__; in(__VA_ARGS__)
using namespace std; void solve();
using ll = long long; using vl = vector<ll>;
using vi = vector<int>; using vvi = vector< vector<int> >;
constexpr int inf = 1001001001;
constexpr ll infLL = (1LL << 61) - 1;
struct IoSetupNya {IoSetupNya() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); cerr << fixed << setprecision(7);} } iosetupnya;
template<typename T, typename U> inline bool amin(T &x, U y) { return (y < x) ? (x = y, true) : false; }
template<typename T, typename U> inline bool amax(T &x, U y) { return (x < y) ? (x = y, true) : false; }
template<typename T, typename U> ostream& operator <<(ostream& os, const pair<T, U> &p) { os << p.first << " " << p.second; return os; }
template<typename T, typename U> istream& operator >>(istream& is, pair<T, U> &p) { is >> p.first >> p.second; return is; }
template<typename T> ostream& operator <<(ostream& os, const vector<T> &v) { int s = (int)v.size(); rep(i,s) os << (i ? " " : "") << v[i]; return os; }
template<typename T> istream& operator >>(istream& is, vector<T> &v) { for(auto &x : v) is >> x; return is; }
void in(){} template <typename T,class... U> void in(T &t,U &...u){ cin >> t; in(u...);}
void out(){cout << "\n";} template <typename T,class... U> void out(const T &t,const U &...u){ cout << t; if(sizeof...(u)) cout << " "; out(u...);}
template<typename T>void die(T x){out(x); exit(0);}
#ifdef NyaanDebug
  #include "NyaanDebug.h"
  #define trc(...) do { cerr << #__VA_ARGS__ << " = "; dbg_out(__VA_ARGS__);} while(0)
  #define trca(v,N) do { cerr << #v << " = "; array_out(v , N);cout << endl;} while(0)
#else
  #define trc(...)
  #define trca(...)
  int main(){solve();}
#endif
using P = pair<int,int>; using vp = vector<P>;
constexpr int MOD = /**/ 1000000007; //*/ 998244353;
//////////

auto ques = [](vi &v){
  cout << "? " << v << endl;
};

// red 0 blue 1
auto ans = []() -> int{
  string s; cin >> s; return (s == "Blue");
};

void solve(){
  ini(N);
  int left = 1 , right = N + 1;
  int lflg , rflg;
  {
    vi v(N); iota(all(v) , 1);
    ques(v); lflg = ans();
    rflg = lflg ^ 1;
  }
  while(left + 1 < right){
    int mid = (left + right) >> 1;
    vi v(N); iota(all(v) , mid);
    ques(v); int mflg = ans();

    if(rflg == mflg){ right = mid ;}
    else { left = mid; }
  }

  // これで1違いを抽出できる
  vi color(2 * N + 1 , -1);
  color[left] = lflg; color[left + N] = rflg;
  // このとき、以下の二つの配列(長さN-1)がプラマイゼロ
  vi s , t;
  for(int i = 1;  i < left ; i++) s.pb(i);
  for(int i = left + 1; i < left + N; i++) t.pb(i);
  for(int i = left + N + 1 ; i <= 2 * N ; i++) s.pb(i);

  each(x , s){
    t.pb(x);
    ques(t); color[x] = ans();
    t.pop_back();
  }
  each(x , t){
    s.pb(x);
    ques(s); color[x] = ans();
    s.pop_back();
  }

  cout << "! ";
  for(int i = 1 ; i <= 2 * N ; i++){
    cout << (color[i] ? "B" : "R");
  }
  cout << endl;



}

Measured memory_bytes: 724