atcoder#ARC081B. [ABC071D] Coloring Dominoes

[ABC071D] Coloring Dominoes

Score : 400400 points

Problem Statement

We have a board with a 2×N2 \times N grid. Snuke covered the board with NN dominoes without overlaps. Here, a domino can cover a 1×21 \times 2 or 2×12 \times 1 square.

Then, Snuke decided to paint these dominoes using three colors: red, cyan and green. Two dominoes that are adjacent by side should be painted by different colors. Here, it is not always necessary to use all three colors.

Find the number of such ways to paint the dominoes, modulo 10000000071000000007.

The arrangement of the dominoes is given to you as two strings S1S_1 and S2S_2 in the following manner:

  • Each domino is represented by a different English letter (lowercase or uppercase).
  • The jj-th character in SiS_i represents the domino that occupies the square at the ii-th row from the top and jj-th column from the left.

Constraints

  • 1N521 \leq N \leq 52
  • S1=S2=N|S_1| = |S_2| = N
  • S1S_1 and S2S_2 consist of lowercase and uppercase English letters.
  • S1S_1 and S2S_2 represent a valid arrangement of dominoes.

Input

Input is given from Standard Input in the following format:

NN

S1S_1

S2S_2

Output

Print the number of such ways to paint the dominoes, modulo 10000000071000000007.

3
aab
ccb
6

There are six ways as shown below:

1
Z
Z
3

Note that it is not always necessary to use all the colors.

52
RvvttdWIyyPPQFFZZssffEEkkaSSDKqcibbeYrhAljCCGGJppHHn
RLLwwdWIxxNNQUUXXVVMMooBBaggDKqcimmeYrhAljOOTTJuuzzn
958681902