#include "bits/stdc++.h"
#define YES "YES"
#define NO "NO"
#define Yes "Yes"
#define No "No"
#define DEFAULT LL ans=solve();\
 	if(ans==NONE){\
 	}else{\
 		cout << ans << endl;\
 	}
#define YESNO three(solve(),(OUT(YES),1),(OUT(NO),0))
#define YesNo three(solve(),OUT(Yes),OUT(No))
#define ECHO OUT(solve())
#define three(A,B,C) ((A)?(B):(C))
#define FOR(i,a,b)  for(LL i=(a);i< (LL)(b);i++)
#define EFOR(i,a,b) for(LL i=(a);i<=(LL)(b);i++)
#define RFOR(i,a,b) for(LL i=(b-1);i>=(LL)(a);i--)
#define REP(i,b) FOR(i,zero,b)
#define rep REP
#define EREP(i,b) EFOR(i,zero,b)
#define RREP(i,b) RFOR(i,zero,b)
#define ALL(c) c.begin(),c.end()
#define UNIQUE(c) sort(ALL(c));c.erase(unique(ALL(c)),c.end())
#define MAX(c) (*max_element(ALL(c)))
#define MIN(c) (*min_element(ALL(c)))
#define MP make_pair
#define FI first
#define SE second
#define SI(x) (LL(x.size()))
#define PB push_back
#define DEBUG(a) OUT(a)
#define DEBUG2(a,b) OUT2(a,b)
#define cat cout << __LINE__ << endl
#define OUT(a) cout << (a) << endl
#define OUT2(a,b) cout << (a) <<" "<<(b) << endl
#define zero 0LL
#define all ALL
#define pb emplace_back
#define eb pb
#define int long long
using namespace std;
template<typename T> inline void maximize(T &a, T b) { a = max(a, b); }
template<typename T> inline void minimize(T &a, T b) { a = min(a, b); }
template<typename T> inline bool middle(T a, T b, T c) { return b <= a && a <= c; }
template<class T> inline bool MX(T &l, const T &r) { return l < r ? l = r, 1 : 0; }
template<class T> inline bool MN(T &l, const T &r) { return l > r ? l = r, 1 : 0; }
typedef int LL;
typedef double ld;
typedef int ut;
typedef vector<ut> VI;
typedef vector<VI> VII;
typedef pair<ut, ut> pr;
typedef pair<ut, pr> ppr;
typedef vector<pr> Vpr;
typedef vector<ppr> Vppr;
typedef tuple<int, int, int, int> tapu;
typedef vector<tapu> Vtapu;
typedef priority_queue<pr, Vpr > PQ;
inline void outputVI(VI x) { REP(i, SI(x)) { cout << three(i, " ", "") << x[i]; }OUT(""); }
const int SIZE1 = 5e5 + 1000;
const int SIZE2 = 5010;
const int SIZE3 = 430;
const int SIZE = SIZE1;
const int MAPSIZE = 40;
const LL p998 = 998244353;
const LL p107 = 1000000007;
const LL p = p107;
const LL INF = 1LL << 60;
const long double EPS = 1e-7;
const LL NONE=-2;
//#define endl "\n"
ut N, M,K,  Q, D, H, W,V;
VI edges[SIZE];
LL vals[SIZE], answer = zero;
//LL A[SIZE],B[SIZE],C[SIZE];
std::chrono::system_clock::time_point starttime,endtime;
LL ABLE;
void st(){
 starttime = std::chrono::system_clock::now(); // 計測開始時間
 }
double ed(){
 
 endtime = std::chrono::system_clock::now();  // 計測終了時間
 double elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(endtime-starttime).count(); //処理に要した時間をミリ秒に変換
 return elapsed;
}
bool ans[SIZE];
bool query(int a,int b){
	if(a==b) return true;
	cout <<"? " <<a << " " << b << endl;
	string s;
	cin >> s;
	return s=="Y";
}
LL solve(){
	LL A,B;
	cin >> A >> B;
	if(A<=B){
		cout <<"Impossible" << endl;
		return NONE;
	}
	queue<int> qu[30];
	N=A+B;
	REP(i,N) qu[0].push(i);

	LL master=0;
	REP(i,30){
		while(qu[i].size()!=1 and !qu[i].empty()){
			int a=qu[i].front();
			qu[i].pop();
			int b=qu[i].front();
			qu[i].pop();
			if(query(a,b)){
				qu[i+1].push(b);
			}
		}
		if(!qu[i].empty()) master=qu[i].front(); 
	}
	string ans;
	REP(i,N){
		if(query(master,i)){
			ans+='1';
		}else{
			ans+='0';
		}
	} 
	cout << "! " << ans << endl;
	return NONE;
}
 signed main() {
 
	LL T=1;

	REP(i,T){
		DEFAULT;

	}
	
//	YesNo;
//	YESNO;
//	three(solve(),OUT("First"),OUT("Second"));
	//cin >> N;
	return 0;
 
}


Measured memory_bytes: 12884