#include <algorithm>
#include <cassert>
#include <cmath>
#include <iostream>
#include <vector>

#define rep(i, n) for (int i = 0; i < (n); i++)
using namespace std;

vector<vector<char>> build(int m, int n, int k) {
  vector<vector<char>> a(m, vector<char>(m, '.'));
  rep(i, m) a[i][i] = '#';
  auto bk = m;
  rep(i, m) {
    rep(j, m) {
      if (a[i][j] == '#') continue;
      if (bk >= n) continue;
      int r_cnt = 0;
      rep(h, m) {
        if (a[h][j] == '#') r_cnt += 1;
      }
      int c_cnt = 0;
      rep(h, m) {
        if (a[i][h] == '#') c_cnt += 1;
      }
      if (r_cnt < k and c_cnt < k) {
        a[i][j] = '#';
        bk += 1;
      }
    }
  }
  return a;
}

int count_bk(vector<vector<char>> &a) {
  int ret = 0;
  rep(i, a.size()) {
    rep(j, a.size()) {
      if (a[i][j] == '#') ret += 1;
    }
  }
  return ret;
}

void print(vector<vector<char>> &a) {
  int m = a.size();
  cout << m << endl;
  rep(i, m) {
    rep(j, m) { cout << a[i][j]; }
    cout << endl;
  }
}

void solve(int n, int k) {
  auto m = (n + k - 1) / k; // m <= n
  m = max(m, (int)ceil(sqrt(n)));
  auto a = build(m, n, k);
  if (count_bk(a) == n) {
    print(a);
  } else {
    auto b = build(m + 1, n, k);
    assert(count_bk(b) == n);
    print(b);
  }
}

int main() {

  int n, k;
  cin >> n >> k;

  solve(n, k);

  for (int i = 50; i <= 60; i++) {
    for (int j = 1; j <= i; j++) {
      // cout << i << " " << j << endl;
      // solve(i, j);
    }
  }
  return 0;
}