Problem9248--ABC293 —— C - Make Takahashi Happy

9248: ABC293 —— C - Make Takahashi Happy

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Time Limit : 1.000 sec  Memory Limit : 512 MiB

Description

### Problem Statement

There is a grid with $H$ horizontal rows and $W$ vertical columns. For two integers $i$ and $j$ such that $1 \leq i \leq H$ and $1 \leq j \leq W$, the square at the $i$-th row from the top and $j$-th column from the left (which we denote by $(i, j)$) has an integer $A_{i, j}$ written on it.

Takahashi is currently at $(1,1)$. From now on, he repeats moving to an adjacent square to the right of or below his current square until he reaches $(H, W)$. When he makes a move, he is not allowed to go outside the grid.

Takahashi will be happy if the integers written on the squares he visits (including initial $(1, 1)$ and final $(H, W)$) are distinct. Find the number of his possible paths that make him happy.

Input

### Input

The input is given from Standard Input in the following format:

```
$H$ $W$
$A_{1, 1}$ $A_{1, 2}$ $\ldots$ $A_{1, W}$
$A_{2, 1}$ $A_{2, 2}$ $\ldots$ $A_{2, W}$
$\vdots$
$A_{H, 1}$ $A_{H, 2}$ $\ldots$ $A_{H, W}$
```

Output

### Output

Print the answer.

Constraints

### Constraints

-   $2 \leq H, W \leq 10$
-   $1 \leq A_{i, j} \leq 10^9$
-   All values in the input are integers.

Sample 1 Input

3 3
3 2 2
2 1 3
1 5 4

Sample 1 Output

3
There are six possible paths:
  • (1,1)→(1,2)→(1,3)→(2,3)→(3,3): the integers written on the squares he visits are 3,2,2,3,4, so he will not be happy.
  • (1,1)→(1,2)→(2,2)→(2,3)→(3,3): the integers written on the squares he visits are 3,2,1,3,4, so he will not be happy.
  • (1,1)→(1,2)→(2,2)→(3,2)→(3,3): the integers written on the squares he visits are 3,2,1,5,4, so he will be happy.
  • (1,1)→(2,1)→(2,2)→(2,3)→(3,3): the integers written on the squares he visits are 3,2,1,3,4, so he will not be happy.
  • (1,1)→(2,1)→(2,2)→(3,2)→(3,3): the integers written on the squares he visits are 3,2,1,5,4, so he will be happy.
  • (1,1)→(2,1)→(3,1)→(3,2)→(3,3): the integers written on the squares he visits are 3,2,1,5,4, so he will be happy.
Thus, the third, fifth, and sixth paths described above make him happy.

Sample 2 Input

10 10
1 2 3 4 5 6 7 8 9 10
11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
31 32 33 34 35 36 37 38 39 40
41 42 43 44 45 46 47 48 49 50
51 52 53 54 55 56 57 58 59 60
61 62 63 64 65 66 67 68 69 70
71 72 73 74 75 76 77 78 79 80
81 82 83 84 85 86 87 88 89 90
91 92 93 94 95 96 97 98 99 100

Sample 2 Output

48620
In this example, every possible path makes him happy.

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