def check_array(array):
    if array[0] == array[2] and array[0] != arr[1]:
        return True
    return False


arr = []
for i in range(3):
    arr.append(list(input()))
if (
    arr[0][0] == arr[2][0]
    and arr[0][0] != arr[1][0]
    and check_array(arr[0])
    and check_array(arr[1])
    and check_array(arr[2])
):
    print("Yes")
else:
    print("No")