from collections import deque

def to_string(grid):
    ans = ''
    for i in range(3):
        for j in range(3):
            ans += grid[i][j]
    return ans

def to_grid(s):
    grid = []
    grid.append([s[0], s[1], s[2]])
    grid.append([s[3], s[4], s[5]])
    grid.append([s[6], s[7], s[8]])
    return grid

def bfs(init_grid):
    que = deque()
    visit = set()

    key = to_string(init_grid)
    flag = False
    for i in range(3):
        for j in range(3):
            if grid[i][j] == 'x':
                pos_i, pos_j = i, j
                flag = True
                break
        if flag:
            break

    que.append( (key, pos_i, pos_j) )
    visit.add(key)

    step = 0
    while len(que) > 0:
        node_num = len(que)
        for _ in range(node_num):
            key, i, j = que.popleft()
            if key == '12345678x':
                return step

            for ii, jj in [(i-1, j), (i+1, j), (i, j-1), (i, j+1)]:
                if ii >= 0 and ii < 3 and jj >= 0 and jj < 3:
                    new_grid = to_grid(key)
                    new_grid[ii][jj], new_grid[i][j] = new_grid[i][j], new_grid[ii][jj]
                    new_key = to_string(new_grid)
                    if new_key not in visit:
                        visit.add(new_key)
                        que.append((new_key, ii, jj))
        step += 1

    return -1

arr = input().split()
grid = [arr[0:3], arr[3:6], arr[6:]]
print(bfs(grid))