#include <cstdio>
#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <string>
#include <cmath>
#include <cstdlib>
#include <cstring>
using namespace std;
#define FI first
#define SE second
#define X first
#define Y second
#define ST first
#define ND second
#define MP make_pair
#define PB push_back
typedef vector<int> VI;
typedef pair<int,int> PII;
typedef long long LL;
typedef long double LD;
typedef double D;
#define REP(i,n) for(int i=0;i<(n);i++)
#define FOR(i,a,b) for(int i=(a);i<=(b);i++)
#define FORD(i,a,b) for(int i=(a);i>=(b);i--)
#define FORE(a,b) for(VAR(a,(b).begin());a!=(b).end();a++)
#define VAR(a,b) __typeof(b) a=(b)
#define SIZE(a) ((int)(a).size())
#define ALL(x) (x).begin(),(x).end()
#define CLR(x,a) memset(x,a,sizeof(x))

const int M = 113;

char s[M][M];
int vis[M*M], skoj[M*M];
int n,m, xx[4]={-1,1,0,0},yy[4]={0,0,-1,1};

int dfs(int e) {
    int i = e / M;
    int j = e % M;
    vis[e] = 1;
    REP(k, 4) if(i+xx[k] >= 0 && i+xx[k] < n && j+yy[k]>=0 && j+yy[k] < m && s[i+xx[k]][j+yy[k]] == '.' && 
            (skoj[(i+xx[k])*M+j+yy[k]] == -1 
             || !vis[skoj[(i+xx[k])*M+j+yy[k]]] 
             && dfs(skoj[(i+xx[k])*M+j+yy[k]]))) {
        skoj[e] = (i+xx[k]) * M + j+yy[k];
        skoj[(i+xx[k]) * M + j+yy[k]] = e;
        return 1;
    }
    return 0;
}

void dfs2(int e) {
    int i = e / M;
    int j = e % M;
    vis[e] = 1;
    s[i][j] = 'B';
    REP(k, 4) if(i+xx[k] >= 0 && i+xx[k] < n && j+yy[k]>=0 && j+yy[k] < m && s[i+xx[k]][j+yy[k]] == '.' && !vis[skoj[(i+xx[k])*M+j+yy[k]]])
    {
        s[i][j] = 'B';
        s[i+xx[k]][j+yy[k]] = 'A';
        dfs2(skoj[(i+xx[k])*M+j+yy[k]]);
    }
    return ;
}


int main() {
    while(scanf("%d %d",&n,&m)==2 && n) {
        REP(i, n) scanf("%s", s[i]);
        REP(i, n) REP(j,m) skoj[i*M+j] = -1;
        int change = 1;
        while(change) {
            change = 0;
            REP(i,n) REP(j,m) vis[i*M+j] = 0;
            REP(i, n) REP(j,m) if((i+j)%2 == 0 && s[i][j] == '.' && !vis[i*M+j] && skoj[i*M+j] == -1 && dfs(i*M+j)) change = 1;
        }
        REP(i,n) REP(j,m) vis[i*M+j] = 0;
        REP(i, n) REP(j,m) if(s[i][j] == '.' && !vis[i*M+j] && skoj[i*M+j] == -1) 
            dfs2(i*M+j);
        REP(i, n) REP(j, m) if(s[i][j] == '.') s[i][j] = 'A';
        REP(i, n) puts(s[i]);
        puts("");
    }
  return 0;
}