/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author aajisaka
 */

#include<bits/stdc++.h>

using namespace std;

void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}
#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

#define SPEED ios_base::sync_with_stdio(false);cin.tie(nullptr)
#define rep(i,n) for(int i=0; i<(int)(n); i++)
#define all(v) v.begin(), v.end()
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }

using ll = long long;
using ull = unsigned long long;
using P = pair<ll, ll>;

constexpr long double PI = 3.14159265358979323846264338327950288L;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

class DGuessThePassword {
public:

    int getLen(const string& a, const string& b) {
      auto na = a.size();
      auto nb = b.size();
      vector<vector<int>> dp(na+1, vector<int>(nb+1));
      rep(i, na+1) dp[i][0] = i;
      rep(i, nb+1) dp[0][i] = i;

      for(int i=1; i<=na; i++) {
        for(int j=1; j<=nb; j++) {
          int m = min(dp[i-1][j]+1, dp[i][j-1]+1);
          if (a[i-1] == b[j-1]) {
            chmin(m, dp[i-1][j-1]);
          } else {
            chmin(m, dp[i-1][j-1]+1);
          }
          dp[i][j] = m;
        }
      }
      return dp[na][nb];
    }

    void solve(istream& cin, ostream& cout) {
      SPEED;

      // check len
      int mi = 1;
      int ma = 128;

#if LOCAL
      string input; cin >> input;
#endif

      while(mi + 1 < ma) {
        auto med = (mi+ma)/2;
        string a;
        rep(i, med) a.push_back('a');
        int b, c;
#if LOCAL
        b = getLen(a, input);
#else
        cout << "? " + a << endl;
        cin >> b;
#endif
        a.push_back('a');
#if LOCAL
        c = getLen(a, input);
#else
        cout << "? " + a << endl;
        cin >> c;
#endif
        if (b+1==c) {
          ma = med;
        } else {
          mi = med;
        }
      }
      int L = ma;
      //debug(L);

      using T = pair<int, string>;
      priority_queue<T, vector<T>, greater<>> que;

      // check len for each characters
      string alnum;
      for(char c='a'; c<='z'; c++) alnum.push_back(c);
      for(char c='A'; c<='Z'; c++) alnum.push_back(c);
      for(char c='0'; c<='9'; c++) alnum.push_back(c);
      for(auto c: alnum) {
        string t;
        t.assign(L, c);
        int b;
#if LOCAL
        b = getLen(t, input);
#else
        cout << "? " + t << endl;
        cin >> b;
#endif
        int cnt = L-b;
        if (cnt==0) continue;
        string s;
        rep(i, cnt) s.push_back(c);
        que.emplace(cnt, s);
      }

      // merge
      while(que.size() > 1) {
        auto p1 = que.top(); que.pop();
        auto p2 = que.top(); que.pop();
        auto len = p1.first + p2.first;
        string s1 = p1.second;
        string s2 = p2.second;
        int now = L - p1.first;
        int idx = 0;
        //cerr << s1 << ',' << s2 << endl;
        for(int i=0; i<=s1.length(); i++) {
          while(idx < s2.length()) {
            //debug(i, idx);
            char c = s2[idx];
            s1.insert(s1.begin()+i, c);
            int b;
#if LOCAL
            //cerr << s1 << endl;
            b = getLen(input, s1);
            //debug(b, now);
#else
            cout << "? " + s1 << endl;
            cin >> b;
#endif
            if (b < now) {
              idx++;
              i++;
              now--;
            } else {
              //cerr << "before: " << s1 << endl;
              s1.erase(s1.begin()+i);
              //cerr << "after: " << s1 << endl;
              break;
            }
          }
        }
        //cerr << s1 << endl;
        que.emplace(len, s1);
      }

      cout << "! " + que.top().second << endl;

    }
};

signed main() {
  DGuessThePassword solver;
  std::istream& in(std::cin);
  std::ostream& out(std::cout);
  solver.solve(in, out);
  return 0;
}

Measured memory_bytes: 3772