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

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

int main() {
	cin >> N >> M; B = max(M, (N + M - 1) / M);

	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;
}