atcoder#ARC069B. [ABC055D] Menagerie

[ABC055D] Menagerie

Score : 500500 points

Problem Statement

Snuke, who loves animals, built a zoo.

There are NN animals in this zoo. They are conveniently numbered 11 through NN, and arranged in a circle. The animal numbered i(2iN1)i (2 \leq i \leq N-1) is adjacent to the animals numbered i1i-1 and i+1i+1. Also, the animal numbered 11 is adjacent to the animals numbered 22 and NN, and the animal numbered NN is adjacent to the animals numbered N1N-1 and 11.

There are two kinds of animals in this zoo: honest sheep that only speak the truth, and lying wolves that only tell lies.

Snuke cannot tell the difference between these two species, and asked each animal the following question: "Are your neighbors of the same species?" The animal numbered ii answered sis_i. Here, if sis_i is o, the animal said that the two neighboring animals are of the same species, and if sis_i is x, the animal said that the two neighboring animals are of different species.

More formally, a sheep answered o if the two neighboring animals are both sheep or both wolves, and answered x otherwise. Similarly, a wolf answered x if the two neighboring animals are both sheep or both wolves, and answered o otherwise.

Snuke is wondering whether there is a valid assignment of species to the animals that is consistent with these responses. If there is such an assignment, show one such assignment. Otherwise, print -1.

Constraints

  • 3N1053 \leq N \leq 10^{5}
  • ss is a string of length NN consisting of o and x.

Input

The input is given from Standard Input in the following format:

NN

ss

Output

If there does not exist an valid assignment that is consistent with ss, print -1. Otherwise, print an string tt in the following format. The output is considered correct if the assignment described by tt is consistent with ss.

  • tt is a string of length NN consisting of S and W.
  • If tit_i is S, it indicates that the animal numbered ii is a sheep. If tit_i is W, it indicates that the animal numbered ii is a wolf.
6
ooxoox
SSSWWS

For example, if the animals numbered 11, 22, 33, 44, 55 and 66 are respectively a sheep, sheep, sheep, wolf, wolf, and sheep, it is consistent with their responses. Besides, there is another valid assignment of species: a wolf, sheep, wolf, sheep, wolf and wolf.

Let us remind you: if the neiboring animals are of the same species, a sheep answers o and a wolf answers x. If the neiboring animals are of different species, a sheep answers x and a wolf answers o.

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3
oox
-1

Print -1 if there is no valid assignment of species.

10
oxooxoxoox
SSWWSSSWWS