#include <stdio.h>

char loops[105][105], visited[105][105];

bool normalChar(char c) {
    return (c == 'X' || c == 'A' || c == 'B');
}

void remap(char letter, int fromx, int fromy, int x, int y) {
    if (loops[x][y] == 'X')
        loops[x][y] = letter;
    else if (loops[x][y] == letter)
        return;
    else if (loops[x][y] == 0)
        printf ("Error!!\n");

    if (normalChar(loops[x+1][y]) &&
        normalChar(loops[x-1][y]) &&
        normalChar(loops[x][y-1]) &&
        normalChar(loops[x][y+1])) {
        printf ("intersect %c at %d %d\n", letter, x, y);
        if (fromx == x-1 && fromy == y  ) remap(letter, x, y, x+1, y);
        else if (fromx == x+1 && fromy == y  ) remap(letter, x, y, x-1, y);
        else if (fromx == x   && fromy == y-1) remap(letter, x, y, x, y+1);
        else if (fromx == x   && fromy == y+1) remap(letter, x, y, x, y-1);
        return;
    } else {
        int allX[] = {1, -1, 0, 0};
        int allY[] = {0, 0, 1, -1};

        for (int i = 0; i < 4; i++)
            if (loops[x + allX[i]][y + allY[i]] == 'X' ||
                loops[x + allX[i]][y + allY[i]] == (letter=='A'?'B':'A')) {
                remap(letter, x, y, x + allX[i], y + allY[i]);
                return;
            }
    }
}

int main() {
    int r, c;
    scanf ("%d %d", &r, &c);

    for (int i = 1; i <= r; i++)
        for (int j = 1; j <= c; j++) {
            scanf(" %c", &loops[i][j]);
            visited[i][j] = 0;
        }

    for (int i = 0; i <= r+1; i++)
        loops[i][0] = loops[i][c+1] = 0;
    for (int i = 0; i <= c+1; i++)
        loops[0][i] = loops[r+1][i] = 0;

    int done[] = {0, 0};
    for (int i = 1; i <= r; i++)
        for (int j = 1; j <= c; j++) {
            if (loops[i][j] == 'A' && done[0] == 0)
                loops[i][j] = 'X', remap('A', i, j, i, j), done[0] = 1;
            if (loops[i][j] == 'B' && done[1] == 0)
                loops[i][j] = 'X', remap('B', i, j, i, j), done[1] = 1;
        }

    for (int i = 1; i <= r; i++) {
        for (int j = 1; j <= c; j++)
            printf("%c", loops[i][j]);
        printf("\n");
    }
    return 0;
}