Problem:
Score : 500 points

Problem Statement

Snuke, who loves animals, built a zoo.

There are N animals in this zoo. They are conveniently numbered 1 through N, and arranged in a circle.
The animal numbered i (2≤i≤N-1) is adjacent to the animals numbered i-1 and i+1. Also, the animal numbered 1 is adjacent to the animals numbered 2 and N, and the animal numbered N is adjacent to the animals numbered N-1 and 1.

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 i answered s_i. Here, if s_i is o, the animal said that the two neighboring animals are of the same species, and if s_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

3 ≤ N ≤ 10^{5}

s is a string of length N consisting of o and x.

Input

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

N
s

Output

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

t is a string of length N consisting of S and W.

If t_i is S, it indicates that the animal numbered i is a sheep. If t_i is W, it indicates that the animal numbered i is a wolf.

Sample Input 1

6
ooxoox

Sample Output 1

SSSWWS

For example, if the animals numbered 1, 2, 3, 4, 5 and 6 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.

Sample Input 2

3
oox

Sample Output 2

-1

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

Sample Input 3

10
oxooxoxoox

Sample Output 3

SSWWSSSWWS

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <bits/stdc++.h>

using namespace std;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n;
	string s;
	cin >> n >> s;
	vector<int> ans;
	for (int i = 0; i < 4; i++) {
		ans.resize(n);
		ans[0] = i % 2;
		ans[1] = i / 2;
		for (int j = 1; j < n - 1; j++) {
			if (s[j] == 'o') {
				if (ans[j] == 0) ans[j + 1] = ans[j - 1];
				else ans[j + 1] = !ans[j - 1];
			}
			else {
				if (ans[j] == 0) ans[j + 1] = !ans[j - 1];
				else ans[j + 1] = ans[j - 1];
			}
		}
		if (s[0] == 'o') {
			if ((ans[0] == 0) ^ (ans[1] == ans.back())) continue;
		} else {
			if ((ans[0] == 0) ^ (ans[1] != ans.back())) continue;
		}
		if (s.back() == 'o') {
			if ((ans.back() == 0) ^ (ans[0] == ans[n - 2])) continue;
		} else {
			if ((ans.back() == 0) ^ (ans[0] != ans[n - 2])) continue;
		}
		for (int j = 0; j < n; j++) {
			cout << "SW"[ans[j]];
		}
		cout << endl;
		return 0;
	}
	cout << -1 << endl;
	return 0;
}