Marching Band Formation Grid

A marching band director has a flat roster of member ID numbers, listed in performance order, and wants to arrange them into a rectangular formation with a given number of rows and columns. The formation must be filled row by row: the first row gets the first batch of IDs in order, the second row gets the next batch, and so on, using every member exactly once.

If the requested number of rows times the number of columns does not exactly equal the number of members on the roster, the formation cannot be built at all.

Input format

• Line 1: an integer k, the number of members on the roster.
• Line 2: k space-separated integers, the member IDs in roster order.
• Line 3: two space-separated integers r and c, the desired number of rows and columns.

Output format

If r * c does not equal k, print a single line containing -1. Otherwise, print r lines, each containing c space-separated member IDs: row i (0-indexed) contains the IDs at roster positions i*c through i*c + c - 1, in order.

Constraints

• 1 <= k <= 10^5
• 1 <= member ID <= 10^9
• 1 <= r, c <= 10^5

6
1 2 3 4 5 6
3 2

1 2
3 4
5 6

4
10 20 30 40
2 3

-1