#include<bits/stdc++.h>
using namespace std;
const int N = 310;
int a[N][N], b[N][N];
int _x[8]={-1,-1,-1,0,0,1,1,1};
int _y[8]={-1,0,1,-1,1,-1,0,1};
bool chk(int n,int m){
    for (int i=1;i<=m;++i) {
        if (b[n-1][i] || b[n][i]) return 0;
    }
    for (int i=1;i<=n;++i) {
        if (b[i][m-1] || b[i][m]) return 0;
    }
    return 1;
}
void work(int n,int m){
    for (int i=1;i<=n;++i){
        for (int j=1;j<=m;++j){
            b[i][j]=0;
            for (int p=0;p<3;++p){
                for (int q=0;q<3;++q){
                    if (i-p<=0 || j-q<=0) continue;
                    b[i][j]^=b[i-p][j-q];
                }
            }
            b[i][j]^=a[i][j];
        }
    }
}
int get(int n,int m){
    for (int i=1;i<=m;++i) b[n-1][i]=b[n][i]=0;
    for (int i=1;i<=n;++i) b[i][m-1]=b[i][m]=0;
//            for (int i=1;i<=n;++i){
//                for (int j=1;j<=m;++j) printf("%d",b[i][j]); puts("");
//            }
    for (int i=1;i<=n;++i){
        for (int j=1;j<=m;++j){
            int tmp=0;
            for (int p=0;p<3;++p){
                for (int q=0;q<3;++q){
                    if (i-p<=0 || j-q<=0) continue;
                    tmp^=b[i-p][j-q];
                }
            }
//            printf("i=%d n=%d %d\n",i,n,(i<=n));
            if (tmp!=a[i][j]) return i;
        }
    }
    return 0;
}
int main(){
//    freopen("1.in","r",stdin);
    int n, m; cin>>m>>n;
    for (int i=1;i<=n;++i){
        string s; cin>>s;
        for (int j=0;j<s.size();++j) a[i][j+1]=(s[j]=='#');
    }
    while(n>=3 && m>=3){
        work(n,m);
        bool ok=chk(n,m);
        if (!ok){
            int x=0, y=0;
//            for (int i=1;i<=n;++i){
//                for (int j=1;j<=m;++j) printf("%d",b[i][j]); puts("");
//            }
            x=get(n,m);
//            printf("x=%d\n",x);
//            for (int i=1;i<=n;++i){
//                for (int j=1;j<=m;++j) printf("%d",a[i][j]); puts("");
//            }puts("");
            for (int i=1;i<=max(n,m);++i){
                for (int j=i+1;j<=max(n,m);++j) swap(a[i][j],a[j][i]);
            }
            swap(n,m);
//            for (int i=1;i<=n;++i){
//                for (int j=1;j<=m;++j) printf("%d",a[i][j]); puts("");
//            }puts("");
            work(n,m);
//            for (int i=1;i<=n;++i){
//                for (int j=1;j<=m;++j) printf("%d",b[i][j]); puts("");
//            }
            y=get(n,m);
//            printf("x=%d y=%d n=%d m=%d\n",x,y,n,m);
            for (int i=1;i<=max(n,m);++i){
                for (int j=i+1;j<=max(n,m);++j) swap(a[i][j],a[j][i]);
            }
            swap(n,m);
            a[x][y]^=1;
//            for (int i=1;i<=n;++i){
//                for (int j=1;j<=m;++j) printf("%d",a[i][j]); puts("");
//            }puts("");
            work(n,m);
            if (!chk(n,m)) {a[x][y]^=1; break;}
        }
//        puts("Yes");

        for (int i=1;i<=n;++i){
            for (int j=1;j<=m;++j) a[i][j]=b[i][j];
        }n-=2; m-=2;
    }
    int U=1, D=n, L=1, R=m;
    while(U<D){bool ed=0; for (int i=1;i<=m;++i) ed|=a[U][i]; if (ed) break; U++;}
    while(U<D){bool ed=0; for (int i=1;i<=m;++i) ed|=a[D][i]; if (ed) break; D--;}
    while(L<R){bool ed=0; for (int i=1;i<=n;++i) ed|=a[i][L]; if (ed) break; L++;}
    while(L<R){bool ed=0; for (int i=1;i<=n;++i) ed|=a[i][R]; if (ed) break; R--;}
    if (L==R && U==D){
        puts("#"); return 0;
    }
    for (int i=U;i<=D;++i){
        for (int j=L;j<=R;++j) printf("%c",a[i][j]?'#':'.'); puts("");
    }
    return 0;
}