Problem L. Lattice Animals

Author:Roman Elizarov (original idea, text)   Time limit:2 sec
Input file:lattice.in   Memory limit:64 Mb
Output file:lattice.out  

Statement

Lattice animal is a set of connected sites on a lattice. Lattice animals on a square lattice are especially popular subject of study and are also known as polyominoes. Polyomino is usually represented as a set of sidewise connected squares. Polyomino with n squares is called n-polyomino.

In this problem you are to find a number of distinct free n-polyominoes that fit into rectangle w × h. Free polyominoes can be rotated and flipped over, so that their rotations and mirror images are considered to be the same.

For example, there are 5 different pentominoes (5-polyominoes) that fit into 2 × 4 rectangle and 3 different octominoes (8-polyominoes) that fit into 3 × 3 rectangle.

Input file format

The input file consists of a single line with 3 integer numbers n, w, and h.

Output file format

Write to the output file a single integer number — the number of distinct free n-polyominoes that fit into rectangle w × h.

Constraints

1 ≤ n ≤ 10; 1 ≤ w, h ≤ n.

Sample tests

No. Input file (lattice.in) Output file (lattice.out)
1
5 1 4
0
2
5 2 4
5
3
5 3 4
11
4
5 5 5
12
5
8 3 3
3

0.106s 0.015s 13