Codeforces Round #Pi (Div. 2)
F
Mausoleum
Codeforces
2400
原题
← E→
翻译中…

King of Berland Berl IV has recently died. Hail Berl V! As a sign of the highest achievements of the deceased king the new king decided to build a mausoleum with Berl IV's body on the main square of the capital.

翻译中…

The mausoleum will be constructed from $2*n*$ blocks, each of them has the shape of a cuboid. Each block has the bottom base of a $1 × 1$ meter square. Among the blocks, exactly two of them have the height of one meter, exactly two have the height of two meters, ..., exactly two have the height of $*n*$ meters.

翻译中…

The blocks are arranged in a row without spacing one after the other. Of course, not every arrangement of blocks has the form of a mausoleum. In order to make the given arrangement in the form of the mausoleum, it is necessary that when you pass along the mausoleum, from one end to the other, the heights of the blocks first were non-decreasing (i.e., increasing or remained the same), and then — non-increasing (decrease or remained unchanged). It is possible that any of these two areas will be omitted. For example, the following sequences of block height meet this requirement:

翻译中…
  • $[1, 2, 2, 3, 4, 4, 3, 1]$;
  • $[1, 1]$;
  • $[2, 2, 1, 1]$;
  • $[1, 2, 3, 3, 2, 1]$.
翻译中…

Suddenly, $*k*$ more requirements appeared. Each of the requirements has the form: "$*h*[*x*_{*i*}]$ sign$_{*i*}$ $*h*[*y*_{*i*}]$", where $*h*[*t*]$ is the height of the $*t*$-th block, and a sign$_{*i*}$ is one of the five possible signs: '=' (equals), '<' (less than), '>' (more than), '<=' (less than or equals), '>=' (more than or equals). Thus, each of the $*k*$ additional requirements is given by a pair of indexes $*x*_{*i*}$, $*y*_{*i*}$ ($1 ≤ *x*_{*i*}, *y*_{*i*} ≤ 2*n*$) and sign sign$_{*i*}$.

翻译中…

Find the number of possible ways to rearrange the blocks so that both the requirement about the shape of the mausoleum (see paragraph 3) and the $*k*$ additional requirements were met.

翻译中…

Input

翻译中…

The first line of the input contains integers $*n*$ and $*k*$ ($1 ≤ *n* ≤ 35$, $0 ≤ *k* ≤ 100$) — the number of pairs of blocks and the number of additional requirements.

翻译中…

Next $*k*$ lines contain listed additional requirements, one per line in the format "$*x*_{*i*}$ sign$_{*i*}$ $*y*_{*i*}$" ($1 ≤ *x*_{*i*}, *y*_{*i*} ≤ 2*n*$), and the sign is on of the list of the five possible signs.

翻译中…

Output

翻译中…

Print the sought number of ways.

翻译中…

样例

Input #1
3 0
Output #1
9
InputCopy OutputCopy
Input #2
3 1
2 > 3
Output #2
1
InputCopy OutputCopy
Input #3
4 1
3 = 6
Output #3
3
InputCopy OutputCopy
题目信息
题号
567F
时间限制
1 s
内存限制
256 MB
标签
动态规划

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。