| Being a confident and accomplished programmer, you are naturally widely | |
| considered to be one of the preeminent dancers of your generation. | |
| Unfortunately this means your dancing is under considerable public scrutiny, | |
| and your critics are often quick to point out when your moves seem to be | |
| getting stale. To prevent such a debacle, you are working on a new maneuver | |
| you're calling "the risky slide". | |
| You haven't worked out some of the details like flourishes or vocalizations | |
| that will accompany the risky slide, but you do know that the core of the move | |
| is a standing slide across a stretch of dance floor. You need to perfect the | |
| execution of your slide, so you are looking for the ideal spot in your | |
| apartment to practice. | |
| You live a fairly ascetic lifestyle, so your apartment is a simple rectangle | |
| with a tiled floor and no furniture or contents of any kind. You will practice | |
| the risky slide by starting out standing at the edge of some tile and running | |
| parallel to one of the walls of the apartment, and at the transition between | |
| some pair of tiles you will go from running to sliding. Your goal is to | |
| achieve the longest possible slide, with distance measured as the number of | |
| tiles you completely traverse during the slide (partial traversal doesn't | |
| count). | |
| This would be an easy problem, but the style of the tiles in your apartment | |
| introduces a complication. Each tile has a particular stickiness that affects | |
| both how well you can run and how well you can slide on it. Each tile has a | |
| stickiness rating between 1 and 9, inclusive. The stickiness affects your | |
| movement as follows: | |
| Running across a tile with stickiness **s** grants **s** units of kinetic | |
| energy. For example, a tile with stickiness 9 is not slippery at all and you | |
| can run across it very efficiently, whereas a tile with stickiness 1 is quite | |
| slippery and does not help you increase your kinetic energy much as you run | |
| across it. | |
| Sliding across a tile with stickiness **s** robs you of **s** units of kinetic | |
| energy. If a tile would reduce your kinetic energy below 0, you stop sliding | |
| somewhere in the middle of the tile and fail to traverse it completely. | |
| ## Input | |
| Your input will consist of a single integer **N** followed by a newline and | |
| **N** test cases. Each case begins with a line containing integers **R** and | |
| **C**, the number of rows and columns, respectively, of tiles in your | |
| apartment. This will be followed by **R** lines, each containing a string of | |
| length **C**, describing the layout of the tiles in your apartment. The value | |
| of each element in these strings is the stickiness as defined above of the | |
| corresponding tile. | |
| ## Output | |
| Output, for each test case and separated by newlines, the maximal possible | |
| number of complete tiles that you can traverse in a single slide through your | |
| apartment. | |
| ## Constraints | |
| **N** ≤ 20 | |
| 1 ≤ **R**, **C** ≤ 50 | |
| Characters representing tiles will all be between '1' and '9', inclusive. | |