#include <bits/stdc++.h>
using namespace std;
using ll = long long int;
using ull = unsigned long long int;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
const int INT_INF = (int)(2e9);
const ll LL_INF = (ll)(2e18);
const int NIL = -1;
static mt19937 _g(time(nullptr));
inline ll randint(ll a, ll b) {
  ll w = (_g() << 31LL) ^ _g();
  return a + w % (b - a + 1);
}
template <typename T>
inline T sign(T x) {
  return T(x > 0) - T(x < 0);
}
template <typename T, typename S>
inline ostream& operator<<(ostream& os, const pair<T, S> p) {
  cout << "[" << p.first << ";" << p.second << "]";
  return os;
}
template <typename T>
inline ostream& operator<<(ostream& os, const vector<T>& v) {
  for (auto el : v) cout << el << " ";
  return os;
}
template <typename T>
inline T fetch() {
  T ret;
  cin >> ret;
  return ret;
}
template <typename T>
inline vector<T> fetch_vec(int sz) {
  vector<T> ret(sz);
  for (auto& elem : ret) cin >> elem;
  return ret;
}
const int MAXN = (int)107;
vector<pii> g[MAXN];
void add_edge(int v, int u, int s) {
  g[v].emplace_back(u, s);
  g[u].emplace_back(v, s);
}
void proc(int l, int r) {
  if (r < l) return;
  cout << "? " << l + 1 << ' ' << r + 1 << endl;
  int sz = r - l + 1;
  int cnt = (sz * (sz + 1)) / 2;
  vector<int> sum(sz + 1, 0);
  for (int i = 0; i < cnt; ++i) {
    auto S = fetch<string>();
    for (auto& el : S) {
      int code = (int)(el - 'a');
      sum[((int)(S).size())] += code;
    }
  };
  int fsum = sum[sz];
  for (int i = 0; i <= sz; ++i) {
    sum[i] = (false ? 1 : sz - i + 1) * fsum - sum[i];
  };
  reverse(sum.begin(), sum.end());
  for (int i = sz; i > 0; --i) {
    sum[i] -= sum[i - 1];
  };
  for (int i = sz; i > 0; --i) {
    sum[i] -= sum[i - 1];
  };
  for (int i = l; i <= r; ++i) {
    int j = r + l - i;
    if (j >= i) {
      int s = sum[i - l + 1];
      add_edge(i, j, s);
    }
  }
}
int used[MAXN], val[MAXN];
void dfs(int v) {
  used[v] = 1;
  for (auto& ed : g[v]) {
    int u = ed.first;
    int s = ed.second;
    if (!used[u]) {
      val[u] = s - val[v];
      dfs(u);
    }
  }
}
void solve() {
  int n = fetch<int>();
  proc(0, n / 2 - 1);
  proc(0, n / 2 - 2);
  proc(0, n - 1);
  memset(val, NIL, sizeof(val));
  for (int i = 0; i < n; ++i) {
    for (auto& ed : g[i]) {
      int j = ed.first;
      int sum = ed.second;
      if (i == j) {
        assert(sum % 2 == 0);
        val[i] = sum / 2;
      }
    }
  }
  for (int i = 0; i < n; ++i) {
    if (val[i] != NIL) {
      dfs(i);
      break;
    }
  }
  for (int i = 0; i < n; ++i) {
    assert(val[i] != NIL);
  }
  string answ(n, '%');
  for (int i = 0; i < n; ++i) answ[i] = 'a' + val[i];
  cout << "! " << answ << endl;
}
int main() {
  solve();
  return 0;
}
