You should know that the first line is A4/4, the second line is A3/ 1, and the second line is A2/ 1, so the remaining two are confirmed. The first line of the third line is A2/ 1. You can try it, that is, A4/4 * A3/65438+. I suggest you draw a 4*4 grid in your notebook. The first line is A4/ 1, A3/ 1, A2/ 1, A 1, and the second line is A3/ 1. A11,a11,a11,the fourth row has all been confirmed ..., 10, the first line: A(4,

The rest are 3 rows and 4 columns.

The first column: A (3,3) = 6

The second column: 3 kinds (fill in the element grid twice first)

Column 3: 2 species

***24*6*3*2=864 species, 2 1234.

432 1

2 143

34 12,2, 1 2 3 4

2 3 4 1

3 4 1 2

4 1 2 3, 1,