Row Coloring, 3 Colors
Count the ways to color a row of N cells with 3 colors so that no two adjacent cells share a color, modulo 109+7.
Input: one integer N.
Output: the count mod 109+7.
Constraints:
- 1 ≤ N ≤ 1018
Sample Tests
Input 1
1
Output 1
3
Input 2
2
Output 2
6
Input 3
3
Output 3
12
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