#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
const int INF = (1<<30);
const ll INFLL = (1ll<<60);
const ll MOD = (ll)(1e9+7);

#define l_ength size

void mul_mod(ll& a, ll b){
	a *= b;
	a %= MOD;
}

void add_mod(ll& a, ll b){
	a = (a<MOD)?a:(a-MOD);
	b = (b<MOD)?b:(b-MOD);
	a += b;
	a = (a<MOD)?a:(a-MOD);
}

bool mp[1010][1010];

int main(void){
	int n,k,m,i,j,p,q;
	cin >> n >> k;
	while(k*k>=n){
		--k;
	}
	++k;
	m = max((n+k-1)/k,k);
	cout << m << endl;
	for(i=0; i<m; i+=k){
		for(p=0; p<k; ++p){
			for(q=0; q<k; ++q){
				if(n && i+p<m && i+q<m){
					mp[i+p][i+q] = true;
					--n;
				}
			}
		}
	}
	for(i=0; i<m; ++i){
		for(j=0; j<m; ++j){
			cout << (mp[i][j]?"#":".");
		}
		cout << endl;
	}
	return 0;
}