#include <bits/stdc++.h>

using namespace std;

using ll = long long;

int calc(int n, int K, vector<int>& v) {
    if (n <= 0) return 0;
    if (n >= K * K) {
        v.push_back(K);
        return calc(n - K * K, K, v) + K;
    }
    int res = 1;
    for (int i = 1; i <= K; i++) {
        if (n <= i * i) {
            res = i;
            break;
        }
    }
    v.push_back(res);
    return calc(n - res * res, K, v) + 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;
    assert(K <= 3);
    vector<int> v;
    int m = calc(n, K, v);
    cout << m << "\n";
    vector<string> ans(m, string(m, '.'));
    int rest = n;
    int beg = 0;
    for (int x : v) {
        for (int i = beg; i < beg + x; i++) {
            for (int j = beg; j < beg + x; j++) {
                if (rest == 0) continue;
                ans[i][j] = '#';
                rest--;
            }
        }
        beg += x;
    }

    for (int i = 0; i < m; i++) {
        cout << ans[i] << "\n";
    }
    assert(judge(ans, n, K));
    return 0;
}