#D8761. Multiple of Nine
Multiple of Nine
Multiple of Nine
Count the number of strings S that satisfy the following constraints, modulo 10^9 + 7.
- The length of S is exactly N.
- S consists of digits (
0
...9
). - You are given Q intervals. For each i (1 \leq i \leq Q), the integer represented by S[l_i \ldots r_i] (the substring of S between the l_i-th (1-based) character and the r_i-th character, inclusive) must be a multiple of 9.
Here, the string S and its substrings may have leading zeroes. For example, 002019
represents the integer 2019.
Constraints
- 1 \leq N \leq 10^9
- 1 \leq Q \leq 15
- 1 \leq l_i \leq r_i \leq N
Input
Input is given from Standard Input in the following format:
N Q l_1 r_1 : l_Q r_Q
Output
Print the number of strings that satisfy the conditions, modulo 10^9 + 7.
Examples
Input
4 2 1 2 2 4
Output
136
Input
6 3 2 5 3 5 1 3
Output
2720
Input
20 10 2 15 5 6 1 12 7 9 2 17 5 15 2 4 16 17 2 12 8 17
Output
862268030
inputFormat
Input
Input is given from Standard Input in the following format:
N Q l_1 r_1 : l_Q r_Q
outputFormat
Output
Print the number of strings that satisfy the conditions, modulo 10^9 + 7.
Examples
Input
4 2 1 2 2 4
Output
136
Input
6 3 2 5 3 5 1 3
Output
2720
Input
20 10 2 15 5 6 1 12 7 9 2 17 5 15 2 4 16 17 2 12 8 17
Output
862268030
样例
6
3
2 5
3 5
1 3
2720