#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <chrono>
#define _USE_MATH_DEFINES
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iostream>
#include <iterator>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <tuple>
#include <utility>
#include <vector>
using namespace std;

#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()

const int INF = 0x3f3f3f3f;
const long long LINF = 0x3f3f3f3f3f3f3f3fLL;
const double EPS = 1e-8;
const int MOD = 1000000007; // 998244353;
const int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
/*-------------------------------------------------*/
int main() {
  cin.tie(nullptr); ios::sync_with_stdio(false);
  // freopen("input.txt", "r", stdin);

  int n, k; cin >> n >> k;
  int lb = 0, m = n;
  while (m - lb > 1) {
    int mid = (lb + m) / 2;
    (min(mid, k) * mid >= n ? m : lb) = mid;
  }
  vector<vector<char> > a(m, vector<char>(m, '.'));
  REP(j, min(m, k)) {
    REP(i, m) {
      if (j + i >= m) break;
      if (n > 0) {
        --n;
        a[i][j + i] = '#';
      }
    }
  }
  for (int i = m - 1; i >= max(m - (k - 1), 0); --i) {
    REP(j, m) {
      if (i + j >= m) break;
      if (n > 0) {
        --n;
        a[i + j][j] = '#';
      }
    }
  }
  cout << m << '\n';
  REP(i, m) {
    REP(j, m) cout << a[i][j];
    cout << '\n';
  }
  return 0;
}