Problem: There are N squares arranged in a row. The squares are numbered 1, 2, ..., N, from left to right.

Snuke is painting each square in red, green or blue. According to his aesthetic sense, the following M conditions must all be satisfied. The i-th condition is:

* There are exactly x_i different colors among squares l_i, l_i + 1, ..., r_i.



In how many ways can the squares be painted to satisfy all the conditions? Find the count modulo 10^9+7.

Constraints

* 1 ≤ N ≤ 300
* 1 ≤ M ≤ 300
* 1 ≤ l_i ≤ r_i ≤ N
* 1 ≤ x_i ≤ 3

Input

Input is given from Standard Input in the following format:


N M
l_1 r_1 x_1
l_2 r_2 x_2
:
l_M r_M x_M


Output

Print the number of ways to paint the squares to satisfy all the conditions, modulo 10^9+7.

Examples

Input

3 1
1 3 3


Output

6


Input

4 2
1 3 1
2 4 2


Output

6


Input

1 3
1 1 1
1 1 2
1 1 3


Output

0


Input

8 10
2 6 2
5 5 1
3 5 2
4 7 3
4 4 1
2 3 1
7 7 1
1 5 2
1 7 3
3 4 2


Output

108

Solution (in PYTHON3):

Solution:
from collections import defaultdict

MOD = 1000000007
iist = lambda: map(int,input().split())

N,M = iist()
Q = defaultdict(list)
for i in range(M):
  l,r,x = iist()
  Q[r].append((l,x-1))

if any(x != 0 for l,x in Q[1]):
  print(0)
  exit(0)

dp = {(0,0):3}
memo = [6]
s = 3

for pk in range(1,N):
  k = pk+1

  for i,c in enumerate(memo):
    c %= MOD
    dp[i,pk] = c
    memo[i] *= 2
    memo[i] %= MOD

  memo.append(2*s%MOD)
  s = 3*s%MOD
  subQ = Q[k]

  for i,j in list(dp.keys()):
    for l,x in subQ:
      if x != (l<=i)+(l<=j):
        c = dp[i,j]
        memo[i] -= c
        memo[j] -= c
        s -= c
        del dp[i,j]
        break

  s %= MOD

print(s)