#include <bits/stdc++.h>
using namespace std;
const int maxn = 5e5 + 555;
vector<multiset<char> > se[2][maxn];
map<multiset<char>, int> vis[maxn];
char str[maxn];
void ask(int a, int b, int id) {
  printf("? %d %d\n", a, b);
  cout.flush();
  int t = 0;
  for (int l = a; l <= b; l++) {
    t += b - l + 1;
  }
  while (t--) {
    scanf("%s", str);
    int len = strlen(str);
    sort(str, str + len);
    multiset<char> tt;
    for (int i = 0; i < len; i++) {
      tt.insert(str[i]);
    }
    se[id][len].push_back(tt);
  }
}
void solve() {
  int n;
  scanf("%d", &n);
  ask(1, n, 0);
  if (n > 1) ask(1, n - 1, 1);
  for (int len = 1; len <= n; len++) {
    for (multiset<char>& ss : se[0][len]) {
      vis[len][ss]++;
    }
  }
  for (int len = 1; len < n; len++) {
    for (multiset<char>& ss : se[1][len]) {
      vis[len][ss]--;
    }
  }
  map<int, int> tot;
  vector<char> ans;
  for (int len = 1; len <= n; len++) {
    for (auto& ite : vis[len]) {
      if (ite.second == 0) continue;
      map<char, int> cnt;
      for (char c : ite.first) {
        cnt[c]++;
      }
      for (auto it : cnt) {
        if (tot[it.first] < it.second) {
          ans.push_back(it.first);
          tot[ans.back()]++;
          break;
        }
      }
      break;
    }
  }
  printf("! ");
  for (int i = ans.size() - 1; i >= 0; i--) cout << ans[i];
  cout << endl;
  cout.flush();
}
signed main() { solve(); }
