Given a chessboard of size $n \times m$, find a sequence of moves for a knight on a chessboard, such that the knight visits every square exactly once. Initially, you can place the knight at any position.
### Input
- A single line contains two integers $n,m$.
### Output
- Print a matrix of size $n\times m$ representing the order of visiting, starting from $1$.
### Constraints
- $1 \le n,m \le 7$.
### Example
Input:
```
5 5
```
Output:
```
1 6 15 10 21
14 9 20 5 16
19 2 7 22 11
8 13 24 17 4
25 18 3 12 23
```
