//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#define rep(i, n) for(int i=0; i<n; ++i)
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
using namespace std;
using ll = int64_t;
using ld = long double;
using P = pair<int, int>;
using vs = vector<string>;
using vi = vector<int>;
using vvi = vector<vi>;
template<class T> using PQ = priority_queue<T>;
template<class T> using PQG = priority_queue<T, vector<T>, greater<T> >;
const int INF = 100010001;
const ll LINF = (ll)INF*INF*10;
template<typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {return a < b && (a = b, true);}
template<typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {return a > b && (a = b, true);}
template<typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) { return is >> p.first >> p.second;}
template<typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) { return os << p.first << ' ' << p.second;}



//head

int n, k;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> k;
  int u = (n+k-1)/k;
  cout << u << endl;
  vs s(u);
  rep(i, u) rep(j, u) {
    s[i] += '#';
  }
  rep(i, u) rep(j, u) {
    if(i <= j and j < i+u-k or i <= j+u and j < i-k) s[i][j] = '.';
  }
  int now = u*k;
  rep(i, u) rep(j, u) {
    if(now == n) break;
    if(s[i][j] == '#') {
      now--;
      s[i][j] = '.';
    }
  }
  rep(i, u) cout << s[i] << '\n';
}