#include <bits/stdc++.h>
using namespace std;
template <typename Arg1, typename Arg2>
ostream &operator<<(ostream &out, const pair<Arg1, Arg2> &x) {
  return out << "(" << x.first << "," << x.second << ")";
}
template <typename Arg1>
ostream &operator<<(ostream &out, const vector<Arg1> &a) {
  out << "[";
  for (const auto &x : a) out << x << ",";
  return out << "]";
}
template <typename Arg1>
ostream &operator<<(ostream &out, const set<Arg1> &a) {
  out << "[";
  for (const auto &x : a) out << x << ",";
  return out << "]";
}
template <typename Arg1, typename Arg2>
ostream &operator<<(ostream &out, const map<Arg1, Arg2> &a) {
  out << "[";
  for (const auto &x : a) out << x << ",";
  return out << "]";
}
template <typename Arg1>
void __trace__(const string name, Arg1 &&arg1) {
  cerr << name << " : " << arg1 << " ] " << endl;
}
template <typename Arg1, typename... Args>
void __trace__(const string names, Arg1 &&arg1, Args &&...args) {
  const string name = names.substr(0, names.find(','));
  cerr << name << " : " << arg1 << " | ";
  __trace__(names.substr(1 + (int)name.size()), args...);
}
clock_t time_p = clock();
void time_taken() {
  time_p = clock() - time_p;
  cerr << "Time Taken : " << (float)(time_p) / CLOCKS_PER_SEC << "\n";
}
const long long mod = 1e9 + 7;
const long long INF = 1e18;
const int nax = 1e5 + 1;
bitset<nax> is_prime;
vector<int> primes;
void sieve(int maxn) {
  is_prime.set();
  is_prime[0] = is_prime[1] = false;
  for (int i = 2; i < maxn; i++) {
    if (!is_prime[i]) continue;
    primes.push_back(i);
    for (int j = i * 2; j < maxn; j += i) {
      is_prime[j] = false;
    }
  }
}
void solve() {}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int getRand(int l, int r) {
  uniform_int_distribution<int> uid(l, r);
  return uid(rng);
}
int n;
void mark(int x);
int del(int x) {
  cout << "B " << x << endl;
  cout << flush;
  mark(x);
  int res;
  cin >> res;
  return res;
}
int decl(int x) {
  cout << "C " << x << endl;
  cout << flush;
  exit(0);
}
int cnt(int x) {
  cout << "A " << x << endl;
  cout << flush;
  int res;
  cin >> res;
  return res;
}
bitset<nax> marked;
int active;
void mark(int p) {
  for (int i = p; i <= n; i += p) {
    if (marked[i]) continue;
    active--;
    marked[i] = 1;
  }
}
int main() {
  ios_base::sync_with_stdio(false), cin.tie(nullptr);
  cin >> n;
  if (n == 1) {
    decl(1);
    return 0;
  }
  active = n;
  sieve(n + 1);
  vector<int> small, big;
  for (int x : primes) {
    if ((long long)x * x <= n) {
      small.push_back(x);
    } else {
      big.push_back(x);
    }
  }
  int ans = 1;
  int m = (int)(big).size();
  const int B = sqrt(m);
  int num_blocks = (m + B - 1) / B;
  for (int i = 0; i < num_blocks; i++) {
    for (int j = i * B; j - i * B < B and j < m; j++) {
      del(big[j]);
    }
    if (cnt(1) == active + 1) {
      for (int j = i * B; j - i * B < B and j < m; j++) {
        if (cnt(big[j]) == 1) {
          ans = big[j];
          break;
        }
      }
      break;
    }
  }
  for (int x : small) {
    del(x);
    if (cnt(x) == 1) {
      long long y = x * x;
      while (y <= n and cnt(y) == 1) {
        y *= x;
      }
      ans *= y / x;
    }
  }
  decl(ans);
  time_taken();
  return 0;
}
