#include <bits/stdc++.h>

#define rep(i, n) for (int i = 0; i < (n); i++)
#define repr(i, n) for (int i = (n) - 1; i >= 0; i--)
#define range(a) a.begin(), a.end()

using namespace std;
using ll = long long;

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  int N, K; cin >> N >> K;
  for (int k = 1;; k++) {
    priority_queue<pair<int, int>> q;
    rep(i, k) {
      q.emplace(K, i);
    }
    vector<vector<int>> ans(k);
    int y = N;
    rep(i, k) {
      vector<pair<int, int>> tmp;
      rep(j, K) if (y > 0 && !q.empty()) {
        tmp.push_back(q.top()); q.pop();
        y--;
      }
      for (auto p : tmp) {
        ans[i].push_back(p.second);
        if (p.first > 1) {
          q.emplace(p.first - 1, p.second);
        }
      }
    }
    if (y == 0) {
      vector<string> grid(k, string(k, '.'));
      rep(i, k) for (int j : ans[i]) grid[i][j] = '#';
      cout << k << endl;
      rep(i, k) cout << grid[i] << '\n';
      return 0;
    }
  }
}