Baekjoon-11559-Puyo Puyo

puyo = []

for _ in range(12):
    line = [c for c in input().strip()]
    puyo.append(line)

explode = 1
total_explode = 0
while explode:
    # use bfs for explosion
    visited = [[0]*6 for _ in range(12)]
    dirs = [(1,0),(-1,0),(0,1),(0,-1)]
    explode = 0
    for i in range(12):
        for j in range(6):
            if puyo[i][j] == '.':
                visited[i][j] = 1
            if visited[i][j] == 0:
                q = [(i,j,puyo[i][j])]
                visited[i][j] = 1
                rocks = [(i,j)]
                while q:
                    x,y,c = q.pop(0)
                    for dx,dy in dirs:
                        if 0<=x+dx<12 and 0<=y+dy<6:
                            if visited[x+dx][y+dy]==0 and puyo[x+dx][y+dy] == c:
                                q.append((x+dx,y+dy,c))
                                visited[x+dx][y+dy] = 1
                                rocks.append((x+dx,y+dy))
                if len(rocks) > 3:
                    for x,y in rocks:
                        puyo[x][y] = '.'
                    explode = 1

    # gravity
    if explode:
        total_explode += 1
        for j in range(6):
            for i in reversed(range(12)):
                if puyo[i][j] == '.':
                    for k in reversed(range(i)):
                        if puyo[k][j] != '.':
                            puyo[i][j] = puyo[k][j]
                            puyo[k][j] = '.'
                            break

print(total_explode)