#include <bits/stdc++.h>

using namespace std;

using ll = long long;

int calc(int n, int K) {
    if (n == 0) return 0;
    if (n >= K * K) return calc(n - K * K, K) + K;
    int res = 0;
    for (int i = 1; i <= K; i++) {
        if (n <= i * i) {
            res = i;
            break;
        }
    }
    return res;
}

bool judge(vector<string>& ans, int n, int K) {
    int m = ans.size();
    for (int i = 0; i < m; i++) {
        int tmp = 0;
        for (int j = 0; j < m; j++) {
            tmp += (ans[i][j] == '#');
        }
        if (tmp > K) return false;
    }

    int cnt = 0;
    for (int j = 0; j < m; j++) {
        int tmp = 0;
        for (int i = 0; i < m; i++) {
            tmp += (ans[i][j] == '#');
            cnt += (ans[i][j] == '#');
        }
        if (tmp > K) return false;
    }
    return (cnt == n);
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n, K;
    cin >> n >> K;

    int m = calc(n, K);
    cout << m << "\n";
    vector<string> ans(m, string(m, '.'));
    int rest = n;
    for (int i = 0; i < m; i++) {
        int ii = i / K;
        for (int j = 0; j < m; j++) {
            int jj = j / K;
            if (ii == jj && rest > 0) {
                rest--;
                ans[i][j] = '#';
            }
        }
        cout << ans[i] << "\n";
    }
    assert(judge(ans, n, K));
    return 0;
}