#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;

//template
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(a);i>(b);i--)
#define ALL(v) (v).begin(),(v).end()
typedef long long int ll; typedef pair<ll, ll> P;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<typename A,size_t N,typename T>void Fill(A(&array)[N],const T &val){fill((T*)array, (T*)(array+N), val);}
const int inf = INT_MAX / 2; const ll INF = LLONG_MAX / 2;
//template end



int main(){
    int n,k; scanf("%d%d",&n,&k);
    int m=(n+k-1)/k,sq=sqrt(n-1e-9)+1;
    chmax(m,sq);
    vector<vector<char>> g(m);
    rep(i,0,m)g[i].resize(m,'.');
    rep(i,0,m)rep(j,0,m){
        if((i+j)%m<k&&n)g[i][j]='#',n--;
    }
    printf("%d\n",m);
    rep(i,0,m){
        rep(j,0,m)cout<<g[i][j];
        puts("");
    }
    return 0;
}