#include <iostream>
#include <algorithm>
#include <cassert>
using namespace std;

int N, M, B;
char c[1009][1009];

int main() {
	cin >> N >> M; B = (N + M - 1) / M;
	assert(1 <= M && M <= N && N <= 1000);
	for (int i = 0; i <= 10000; i++) { if (i*i < N) B = max(B, i + 1); }

	for (int i = 0; i < B; i++) { for (int j = 0; j < B; j++) c[i][j] = '.'; }
	for (int i = 0; i < M; i++) {
		for (int j = 0; j < B; j++) {
			if (N > 0) { c[j][(i + j) % B] = '#'; N--; }
		}
	}
	cout << B << endl;
	for (int i = 0; i < B; i++) {
		for (int j = 0; j < B; j++) cout << c[i][j]; cout << endl;
	}
	return 0;
}