#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<long long> VL;
typedef vector<vector<long long>> VVL;
typedef pair<int,int> Pair;
typedef tuple<int,int,int> tpl;

#define ALL(a)  (a).begin(),(a).end()
#define SORT(c) sort((c).begin(),(c).end())
#define REVERSE(c) reverse((c).begin(),(c).end())
#define EXIST(m,v) (m).find((v)) != (m).end()
#define LB(a,x) lower_bound((a).begin(), (a).end(), x) - (a).begin()
#define UB(a,x) upper_bound((a).begin(), (a).end(), x) - (a).begin()

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define RFOR(i,a,b) for(int i=(a)-1;i>=(b);--i)
#define RREP(i,n) RFOR(i,n,0)

#define en "\n"

constexpr double EPS = 1e-9;
constexpr double PI  = 3.1415926535897932;
constexpr int INF = 2147483647;
constexpr long long LINF = 1LL<<60;
constexpr long long MOD = 1000000007; // 998244353;

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;}

template<class T>
void remove_duplication(vector<T> &v){
    sort(v.begin(), v.end());
	v.erase(unique(v.begin(), v.end()), v.end());
}

void check(vector<string>& S){
    int n = S.size(), m = S[0].size();
    vector<Pair> v;
    REP(i,m)FOR(j,i+1,m){
        int c1=0, c2=0;
        REP(k,n) if(S[k][i]==S[k][j]) c1++; else c2++;
        v.emplace_back(c1,c2);
    }
    remove_duplication(v);
    if(v.size()==1) cout << "Yes" << en;
    else cout << "No" << en;
    return;
}

string rev(string& s){
    int n = s.size();
    string ret(n,'A');
    REP(i,n) if(s[i]=='A') ret[i]='B';
    return ret;
}

void Main(){
    int N; cin >> N;
    vector<string> s;
    REP(i,N){
        vector<string> t; t.emplace_back(string(1<<i,'A') + string(1<<i,'B'));

        for(string u : s){
            t.emplace_back(""); t.back() += u; t.back() += u;
            t.emplace_back(""); t.back() += u; t.back() += rev(u);
        }

        swap(s,t);
    }

    //check(s);

    int K = s.size();
    cout << K << en;
    REP(i,K) cout << s[i] << en;
    return;
}

int main(void){
    cin.tie(0);cout.tie(0);ios_base::sync_with_stdio(0);cout<<fixed<<setprecision(15);
    int t=1; //cin>>t;
    while(t--) Main();
    return 0;
}
//@Author: KeinYukiyoshi

// clang-format off
#include <bits/stdc++.h>
//#pragma GCC optimize("Ofast")
//#pragma GCC target("avx")
#define int long long
using namespace std;
#define stoi stoll
#define fi first
#define se second
#define rep(i, n) for(int i=0, i##_len=(n); i<i##_len; i++)
#define rep2(i, a, b) for (int i = (int)(a), i##_len=(b); i < i##_len; i++)
#define rep3(i, a, b) for (int i = (int)(a), i##_len=(b); i >= i##_len; i--)
#define FOR(i, a) for (auto &i: a)
#define ALL(obj) begin(obj), end(obj)
#define _max(x) *max_element(ALL(x))
#define _min(x) *min_element(ALL(x))
#define _sum(x) accumulate(ALL(x), 0LL)

const int MOD   = 1000000007;
// const int MOD    = 998244353;
const int INF    = (int)(1e13 + 7);
const double EPS = 1e-8;
const double PI  = 3.14159265358979;
template <class T> using V = vector<T>;
template <class T> using VV = vector<vector<T>>;
template <class T> using VVV = vector<vector<vector<T>>>;
template <class T, class S>  using P = pair<T, S>;
template<class T> bool chmax(T &a, const T &b) {if (a < b) {a = b;return true;}return false;}
template<class T> bool chmin(T &a, const T &b) {if (b < a) {a = b;return true;}return false;}
int _ceil(int a, int b) { return (a >= 0 ? (a + (b - 1)) / b : (a - (b - 1)) / b); }
int _mod(int a) {return a >= 0 ? a % MOD : a - (MOD * _ceil(a, MOD));}
int _pow(int a, int b) {int res = 1;for (a %= MOD; b; a = a * a % MOD, b >>= 1)if (b & 1) res = res * a % MOD;return res;}
struct mint {long long x;mint(long long x = 0) : x((x % MOD + MOD) % MOD) {}mint operator-() const { return mint(-x); }mint &operator+=(const mint a) {if ((x += a.x) >= MOD) x -= MOD;return *this;}mint &operator-=(const mint a) {if ((x += MOD - a.x) >= MOD) x -= MOD;return *this;}mint &operator*=(const mint a) { (x *= a.x) %= MOD;return *this; }mint operator+(const mint a) const { return mint(*this) += a; }mint operator-(const mint a) const { return mint(*this) -= a; } mint operator*(const mint a) const { return mint(*this) *= a; }mint pow(long long t) const {if (!t) return 1;mint a = pow(t >> 1);a *= a;if (t & 1) a *= *this;return a;}mint inv() const { return pow(MOD - 2); }mint &operator/=(const mint a) { return *this *= a.inv(); }mint operator/(const mint a) const { return mint(*this) /= a; }};istream &operator>>(istream &is, mint &a) { return is >> a.x; }ostream &operator<<(ostream &os, const mint &a) { return os << a.x; }
// clang-format on

class AABC {
public:
  static void solve(istream &cin, ostream &cout) {
    cin.tie(nullptr);
    cout.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(15);
    int K;
    cin >> K;
    int ans = 0;
    rep2(a, 1, K + 1) {
      rep2(b, 1, _ceil(K, a) + 1) {
        if (a * b <= K) {
          ans += K / (a * b);
        }
      }
    }
    cout << ans << endl;
  }
};


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

