题目描述
Takahashi has an $N \times N$ grid. The square at the i-th row and the j-th column of the grid is denoted by (i,j). Particularly, the top-left square of the grid is (1,1), and the bottom-right square is (N,N).
An integer, 0 or 1, is written on M of the squares in the Takahashi's grid. Three integers a_i,b_i and c_i describe the i-th of those squares with integers written on them: the integer c_i is written on the square (a_i,b_i).
Takahashi decides to write an integer, 0 or 1, on each of the remaining squares so that the condition below is satisfied. Find the number of such ways to write integers, modulo 998244353.
- For all $1\leq i < j\leq N,$ there are even number of 1s in the square region whose top-left square is (i,i) and whose bottom-right square is (j,j).
Constraints
- $2 \leq N \leq 10^5$
- $0 \leq M \leq min(5 \times 10^4,N^2)$
- $1 \leq a_i,b_i \leq N(1\leq i\leq M)$
- $0 \leq c_i \leq 1(1\leq i\leq M)$
- If $i \neq j$, then $(a_i,b_i) \neq (a_j,b_j)$.
- All values in input are integers.
Input
Input is given from Standard Input in the following format:
N M
a_1 b_1 c_1
:
a_M b_M c_M
Output
Print the number of possible ways to write integers, modulo 998244353.
Examples
Input
3 3
1 1 1
3 1 0
2 3 1
Output
8
Input
4 5
1 3 1
2 4 0
2 3 1
4 2 1
4 4 1
Output
32
Input
3 5
1 3 1
3 3 0
3 1 0
2 3 1
3 2 1
Output
0
Input
4 8
1 1 1
1 2 0
3 2 1
1 4 0
2 1 1
1 3 0
3 4 1
4 4 1
Output
4
Input
100000 0
Output
342016343
输入格式
见题面
输出格式
见题面