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;
const int pi=3.1415926535897932384626433832795;
const int dx[]={0,1,0,-1};
const int dy[]={1,0,-1,0};
#define ll long long
#define inf int(1e9+7)
#define pb push_back
#define mp make_pair
char s[100005];
char t[100005];
int a[100005],n;
int main()
{
	cin>>n>>s;
	for(int i=0;i<2;i++)
		for(int j=0;j<2;j++)
		{
			if(i==0)
				a[0]=0;
			else
				a[0]=1;
			if(j==0)
				a[1]=0;
			else
				a[1]=1;
			for(int k=2;k<n;k++)
			{
				if(s[k-1]=='o')
				{
					if(a[k-1]==0)
						a[k]=a[k-2];
					else
						a[k]=1-a[k-2];
				}
				else
				{
					if(a[k-1]==0)
						a[k]=1-a[k-2];
					else
						a[k]=a[k-2];
				}
			}
			if(s[n-1]=='o')
			{
				if(a[n-1]==0)
				{
					if(a[n-2]!=a[0])
						continue;
				}
				else
				{
					if(a[n-2]==a[0])
						continue;
				}
			}
			else
			{
				if(a[n-1]==0)
				{
					if(a[n-2]==a[0])
						continue;
				}
				else
				{
					if(a[n-2]!=a[0])
						continue;
				}
			}
			if(s[0]=='o')
			{
				if(a[0]==0)
				{
					if(a[n-1]!=a[1])
						continue;
				}
				else
				{
					if(a[n-1]==a[1])
						continue;
				}
			}
			else
			{
				if(a[0]==0)
				{
					if(a[n-1]==a[1])
						continue;
				}
				else
				{
					if(a[n-1]!=a[1])
						continue;
				}
			}
			for(int k=0;k<n;k++)
			{
				if(a[k]==0)
					t[k]='S';
				else
					t[k]='W';
			}
			cout<<t;
			return 0;
		}
	puts("-1");
	return 0;
}