#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++) {
    if ((k / K) * K * K + (k % K) * (k % K) >= N) {
      vector<string> ans(k, string(k, '.'));
      rep(l, k / K) {
        rep(i, K) rep(j, K) if (N > 0) {
          ans[l * K + i][l * K + j] = '#';
          N--;
        }
      }
      rep(i, k % K) rep(j, k % K) if (N > 0) {
        ans[k / K * K + i][k / K * K + j] = '#';
        N--;
      }
      cout << k << endl;
      rep(i, k) cout << ans[i] << endl;
      break;
    }
  }
}