#define _USE_MATH_DEFINES
#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define MT make_tuple
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
#define RT return
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
using vll = vector<ll>;

char A[1010][1010];

void solve() {
    MEM(A, '.');

    int N, K;
    cin >> N >> K;

    int x = 0, mi = INT_MAX, R = 0;
    for (int i = 1; i <= K; ++i) {
        int q = N / (i*i);
        int r2 = N % (i*i);
        int r = 1;
        while (r*r < r2)++r;
        if (i*q + r < mi) {
            x = i;
            R = r;
            mi = i * q + r;
        }
    }

    int M = 0;
    while (N > 0) {
        if (N < x*x) {
            [&] {
                rep(i, R)rep(j, R) {
                    A[M + i][M + j] = '#';
                    if (!--N)return;
                }
            }();
            M += R;
        } else {
            rep(i, x)rep(j, x)A[M + i][M + j] = '#';
            N -= x * x;
            M += x;
        }
    }

    cout << M << endl;
    rep(i, M) {
        rep(j, M)cout << A[i][j];
        cout << endl;
    }
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout << fixed << setprecision(15);
	solve();
	return 0;
}