#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
using namespace chrono;
#define all(a) a.begin(), a.end()
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<double> vd;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<int, ll> pil;
typedef pair<ll, int> pli;
typedef tuple<int, int, int> tpl;
template<class T1, class T2>
istream &operator>>(istream &in, pair<T1, T2> &P){
	in >> P.first >> P.second;
	return in;
}
template<class T>
istream &operator>>(istream &in, vector<T> &arr){
	for(auto &x: arr) in >> x;
	return in;
}
template<class T>
istream &operator>>(istream &in, deque<T> &arr){
	for(auto &x: arr) in >> x;
	return in;
}
template<class T1, class T2>
ostream &operator<<(ostream &out, const pair<T1, T2> &P){
	out << P.first << " " << P.second << "\n";
	return out;
}
template<class T>
ostream &operator<<(ostream &out, const vector<T> &arr){
	for(auto &x: arr) out << x << ' '; cout << "\n";
	return out;
}
template<class T>
ostream &operator<<(ostream &out, const deque<T> &arr){
	for(auto &x: arr) out << x << ' '; cout << "\n";
	return out;
}
template<class T>
ostream &operator<<(ostream &out, const set<T> &arr){
	for(auto &x: arr) out << x << ' '; cout << "\n";
	return out;
}
template<class T1, class T2>
ostream &operator<<(ostream &out, const map<T1, T2> &arr){
	for(auto &x: arr) out << x << ' '; cout << "\n";
	return out;
}
template<class T>
using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
mt19937 rnd(time(0));
 

 
int main(){
	cin.tie(0)->sync_with_stdio(0);
	auto query = [&](const deque<int> &arr){ // more red ball?
		cout << "? ";
	    for(auto x: arr){
	    	cout << x << " ";
	    }
	    cout << endl;
	    string s;
	    cin >> s;
	    if(s == "-1"){
	    	exit(0);
	    }
	    if(s == "Red"){
	    	return true;
	    }
	    else{
	    	return false;
	    }
	};
	int n;
	cin >> n;
	deque<int> a(n);
	iota(all(a), 1);
	vi res(2 * n + 1, -1);
	int init = query(a);
	int left = 1, right = n + 1;
	while(right - left > 1){
		int mid = left + right >> 1;
		a.clear();
		for(int i = 0; i < n; i ++){
			a.push_back(mid + i);
		}
		if(query(a) == init){
			left = mid;
		}
		else{
			right = mid;
		}
	}
	a.clear();
	for(int i = 0; i < n; i ++){
		a.push_back(left + 1 + i);
	}
	int l = a.front(), r = a.back();
	res[l - 1] = init, res[r] = !init;
	for(int i = 1; i <= 2 * n; i ++){
		if(i < l - 1 || i > r){
			a.pop_back();
			a.push_back(i);
			res[i] = query(a);
		}
	}
	a.clear();
	vi cnt(2);
	int s = (n - 1) / 2;
	for(int i = 1; cnt[0] < s || cnt[1] < s; i ++){
		if(res[i] != -1 && cnt[res[i]] < s){
			cnt[res[i]] ++;
			a.push_back(i);
		}
	}
	for(int i = l; i < r; i ++){
		a.push_back(i);
		res[i] = query(a);
		a.pop_back();
	}
	cout << "! ";
	for(int i = 1; i <= 2 * n; i ++){
		cout << (res[i] ? 'R' : 'B');
	}
	return 0;
}
/*
*/
 
//////////////////////////////////////////////////////////////////////////////////////////////////////
//                                                                                                  //
//                                                                                                  //
//                                              _____________                                       //
//             ++++++++++                ___------------------\                                     //
//           +++`+``+`+`++++        ///`````````````````````````````\                               //
//           ++`+`+``+++`++++  /////```````````````````````````````````\                            //
//           +++`++`+`+``+++/////`````````````````````````````````````````\                         //
//             +++`++`+``+///```````````|```````````````````````````````````\                       //
//          ____++++/++++/`````````````/````````|````````|```````````````````\                      //
//        /  /  / |    //``````````````|````````|```````|````````|````````````\                     //
//       /  /  /  | ///````````/```````|```````||```````|````````|``````\```````\                   //
//       | /  /   |///`````````|``````/````````|````````|````````|```````|```````\                  //
//       |/   |   |//``|```````|``````|````````|`````````|```````|```````|````````\                 //
//       /\___|__//`|``|```````|`    |      ``:|````````|:```````|```````|```|`````|                //
//      /     /  /``|``|``````|/     |        :|     ```:|```````|```````|``++````++                //
//     /     / //```|``|``````|      |        |:        :|    ```|```````|```++``++`\               //
//     |    /  /````|``|``````/    _.::::.    |          |      |    ````|```|`++`\`|               //
//     |   /   |````|``|`````|            `                    |       ``|```++``++`|               //
//     |  /    |````|``|`````|                                 :         |``++````++|               //
//     | /     /````|``|`````|                              _.-:::.      |..`|``.`|.|               //
//     |/     /`````|``|`````|                                     `     |```|````|`|               //
//    /|      |`````|``|`````|                    :'                    .|```|````|.|               //
//   / |      |`````|``|`````|                                         /|-|``|````|`|               //
//  /  |      |`````|```\````|                                        / ||```|````|``\              //
// /   |      |`````|````|```|::                                    /_| ||```|````|``|              //
//            |`````|````|```|:|:.        `.._                    .\___/:|```|````|``|              //
//            |`````\````|```|:|::-          ``:::....           -:|:|:::|```|````|``|              //
//            |``````|```|```|:|::`|.                          .:::|:|:::|```|````|``|              //
//             \`````|```|```|:|::/|--.                     .`:|:::|:|:::/```|````|``|              //
//              |````|```|```\:|:|:|-----             _..-:|:|:|:::|:|::|````|````|`/               //
//              |````|```|````\|:|:|-------.____.....------|/::|:::|:|::|````|````|`|               //
//              |````|```|\````\:|/\___________    ________/\--\:::|:|::|````/````|`|               //
//              |````\```| \```|:/-------------\  /----------\``\::|:|::|```/`````|`|               //
//              |`````|``|  \``|/---------------\/------------\_________|```|`````|`|               //
//                                                                                                  //
//////////////////////////////////////////////////////////////////////////////////////////////////////
//                                                                                                  //
//                                        Created by Aeren                                          //
//                                                                                                  //
//////////////////////////////////////////////////////////////////////////////////////////////////////

Measured memory_bytes: 724