g = [input() for _ in range(3)]
direction = [(1, 0), (0, 1), (-1, 0), (0, -1)]
for i in range(3):
    for j in range(3):
        ok = True
        for dx, dy in direction:
            ni, nj = i + dx, j + dy
            if 0 <= ni < 3 and 0 <= nj < 3:
                if g[i][j] == g[ni][nj]:
                    ok = False

        if not ok:
            print("No")
            exit()
print("Yes")