#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
#include<cassert>
#include<complex>
#include<numeric>
using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
const ll mod = 1000000007;
const ll INF = (1e+18) + 7;
typedef pair<int, int>P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;
typedef long double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-8;
const ld pi = acos(-1.0);
//typedef vector<vector<ll>> mat;
typedef vector<int> vec;

ll mod_pow(ll a, ll n, ll m) {
	ll res = 1;
	while (n) {
		if (n & 1)res = res * a%m;
		a = a * a%m; n >>= 1;
	}
	return res;
}

struct modint {
	ll n;
	modint() :n(0) { ; }
	modint(ll m) :n(m) {
		if (n >= mod)n %= mod;
		else if (n < 0)n = (n%mod + mod) % mod;
	}
	operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint &a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= mod; return a; }
modint operator-=(modint &a, modint b) { a.n -= b.n; if (a.n < 0)a.n += mod; return a; }
modint operator*=(modint &a, modint b) { a.n = ((ll)a.n*b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, int n) {
	if (n == 0)return modint(1);
	modint res = (a*a) ^ (n / 2);
	if (n % 2)res = res * a;
	return res;
}

ll inv(ll a, ll p) {
	return (a == 1 ? 1 : (1 - p * inv(p%a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }

const int max_n = 1 << 18;
modint fact[max_n], factinv[max_n];
void init_f() {
	fact[0] = modint(1);
	for (int i = 0; i < max_n - 1; i++) {
		fact[i + 1] = fact[i] * modint(i + 1);
	}
	factinv[max_n - 1] = modint(1) / fact[max_n - 1];
	for (int i = max_n - 2; i >= 0; i--) {
		factinv[i] = factinv[i + 1] * modint(i + 1);
	}
}
modint comb(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[b] * factinv[a - b];
}
using mP = pair<modint, modint>;

int dx[4] = { 0,1,0,-1 };
int dy[4] = { 1,0,-1,0 };

struct uf {
private:
	vector<int> par, ran;
public:
	uf(int n) {
		par.resize(n, 0);
		ran.resize(n, 0);
		rep(i, n) {
			par[i] = i;
		}
	}
	int find(int x) {
		if (par[x] == x)return x;
		else return par[x] = find(par[x]);
	}
	void unite(int x, int y) {
		x = find(x), y = find(y);
		if (x == y)return;
		if (ran[x] < ran[y]) {
			par[x] = y;
		}
		else {
			par[y] = x;
			if (ran[x] == ran[y])ran[x]++;
		}
	}
	bool same(int x, int y) {
		return find(x) == find(y);
	}
};

int n;
int tmp = 0;
bool query(int a, int b) {
	tmp++;
	assert(tmp <= 2 * n);
	cout << "? " << a << " " << b << endl;
	char t; cin >> t;
	return (t == 'Y');
}
void solve() {
	int a, b; cin >> a >> b;
	if (a <= b) {
		cout << "Impossible" << endl; return;
	}
	
	n = a + b;
	uf u(n);
	vector<int> las;
	queue<int> q;
	rep(i, n)q.push(i);
	vector<P> v;


	vector<bool> chked(n, false);
	int sz;
	while (!q.empty()) {
		int cur = q.front(); q.pop();
		if (las.empty()) {
			las.push_back(cur);
			sz = 1;
			if (sz > b)break;
			continue;
		}
		bool f = query(las.back(), cur);
		if (!f) {
			v.push_back({ las.back(),cur });
			las.pop_back();
			if (v.size() == b)break;
		}
		else {
			f = query(cur, las.back());
			if (!f) {
				chked[u.find(las.back())] = true;
				q.push(cur);
				b -= las.size();
				las.clear();
				if (b == v.size()) {
					break;
				}
			}
			else {
				u.unite(las.back(), cur);
				las.push_back(cur);
				sz++;
				if (sz > b)break;
			}
		}
	}
	string ans;
	ans.resize(n, '0');
	int sta = -1;
	if (v.size()!=b) {
		sta = las[0];
	}
	else {
		//while (v.size() != b);
		//while (q.empty());
		if (q.empty())sta = las[0];
		else {
			sta = q.front(); q.pop();
		}
		while (!q.empty()) {
			int id = q.front(); q.pop();
			chked[u.find(id)] = true;
			ans[u.find(id)] = '1';
		}
	}
	//while (sta < 0);
	chked[u.find(sta)] = true;
	ans[u.find(sta)] = '1';
	rep(i,n) {
		int p = u.find(i);
		if (!chked[p]){
			chked[p] = true;
			bool f = query(sta, p);
			if(f)ans[p] = '1';
		}
		ans[i] = ans[p];
	}
	cout << "! " << ans << endl;
}



signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//cout << fixed << setprecision(10);
	//init_f();
	//init();
	//int t; cin >> t; rep(i, t)solve();
	solve();
	stop
		return 0;
}


Measured memory_bytes: 4948