#include <bits/stdc++.h>
using namespace std;
inline char gc() {
  static char buf[100000], *p1 = buf, *p2 = buf;
  return p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, 100000, stdin), p1 == p2)
             ? EOF
             : *p1++;
}
inline long long read() {
  long long x = 0;
  char ch = getchar();
  bool positive = 1;
  for (; !isdigit(ch); ch = getchar())
    if (ch == '-') positive = 0;
  for (; isdigit(ch); ch = getchar()) x = x * 10 + ch - '0';
  return positive ? x : -x;
}
inline void write(long long a) {
  if (a < 0) {
    a = -a;
    putchar('-');
  }
  if (a >= 10) write(a / 10);
  putchar('0' + a % 10);
}
inline void writeln(long long a) {
  write(a);
  puts("");
}
inline void wri(long long a) {
  write(a);
  putchar(' ');
}
inline unsigned long long rnd() {
  return ((unsigned long long)rand() << 30 ^ rand()) << 4 | rand() % 4;
}
const int N = 105;
int to[N << 1];
vector<string> A[N], B[N], C[N];
char ch[N];
void Read(vector<string> a[N], int l, int r) {
  cout << "? " << l << " " << r << endl;
  int cnt = (r - l + 2) * (r - l + 1) / 2;
  for (int i = (int)(1); i <= (int)(cnt); i++) {
    string s;
    cin >> s;
    a[s.length()].push_back(s);
  }
}
int main() {
  int n = read();
  if (n <= 3) {
    string ans, s;
    for (int i = (int)(1); i <= (int)(n); i++) {
      cout << "? " << i << " " << i << endl;
      cin >> s;
      ans += s;
    }
    cout << "! " << ans << endl;
    return 0;
  }
  Read(A, 1, n);
  int len = (n + 1) / 2;
  Read(B, 1, len);
  Read(C, 1, len - 1);
  for (int i = (int)(1); i <= (int)(len); i++) {
    string ans;
    int sum = 0;
    for (auto j : B[i])
      for (auto k : j) sum ^= k;
    for (auto j : C[i])
      for (auto k : j) sum ^= k;
    for (int j = (int)(len - i + 2); j <= (int)(len); j++) sum ^= ch[j];
    ch[len - i + 1] = sum;
  }
  for (int i = (int)(2); i <= (int)(n - len + 1); i++) {
    memset((to), 0, sizeof(to));
    for (auto j : A[i])
      for (auto k : j) to[k]++;
    for (auto j : B[i])
      for (auto k : j) to[k]--;
    for (int j = (int)(len); j >= (int)(len - i + 2); j--)
      to[ch[j]] -= i - (len - j + 1);
    for (int j = (int)(n - i + 3); j <= (int)(n); j++) to[ch[j]] -= n - j + 1;
    for (int j = (int)('a'); j <= (int)('z'); j++) {
      if (to[j] % i) ch[n - i + 2] = j;
      to[j] = 0;
    }
  }
  cout << "! " << ch + 1 << endl;
}
