Problem:
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`.

Incorrect submission (verdict: Wrong Answer):
import sys
a = int(input())
b = list(input())
frag = 0
parks = [list("ss"),list("sw"),list("ws"),list("ww")]
for park in parks:
    for i in range(len(b)-2):
        if b[i+1] == "o":
            if park[i]=="s" and park[i+1]=="s":
                park.append("s")
            elif park[i]=="s" and park[i+1]=="w":
                park.append("w")
            elif park[i]=="w" and park[i+1]=="s":
                park.append("w")
            elif park[i]=="w" and park[i+1]=="w":
                park.append("s")
        elif b[i+1] == "x":
            if park[i]=="s" and park[i+1]=="s":
                park.append("w")
            elif park[i]=="s" and park[i+1]=="w":
                park.append("s")
            elif park[i]=="w" and park[i+1]=="s":
                park.append("s")
            elif park[i]=="w" and park[i+1]=="w":
                park.append("w")
    if b[-1]=="o":
        if park[-1] == "s":
            if park[0]==park[-2]:
                print (''.join(park))
                frag = 1
                break
        if park[-1] == "w":
            if park[0]!=park[-2]:
                print (''.join(park))
                frag = 1
                break
    if b[-1]=="x":
        if park[-1] == "s":
            if park[0]!=park[-2]:
                print (''.join(park))
                frag = 1
                break
        if park[-1] == "w":
            if park[0]==park[-2]:
                print (''.join(park))
                frag = 1
                break
if frag == 0:
    print(-1)
        

Fixed, accepted submission:
a = int(input())
b = list(input())
frag = 0
parks = [list("SS"),list("SW"),list("WS"),list("WW")]
for park in parks:
    for i in range(len(b)-2):
        if b[i+1] == "o":
            if park[i]=="S" and park[i+1]=="S":
                park.append("S")
            elif park[i]=="S" and park[i+1]=="W":
                park.append("W")
            elif park[i]=="W" and park[i+1]=="S":
                park.append("W")
            elif park[i]=="W" and park[i+1]=="W":
                park.append("S")
        elif b[i+1] == "x":
            if park[i]=="S" and park[i+1]=="S":
                park.append("W")
            elif park[i]=="S" and park[i+1]=="W":
                park.append("S")
            elif park[i]=="W" and park[i+1]=="S":
                park.append("S")
            elif park[i]=="W" and park[i+1]=="W":
                park.append("W")
    
    frag2 = 0
    if b[0]=="o":
        if park[0] == "S":
            if park[-1]==park[1]:
                frag2 = 1 
        if park[0] == "W":
            if park[-1]!=park[1]:
                frag2 = 1
    if b[0]=="x":
        if park[0] == "S":
            if park[-1]!=park[1]:
                frag2 = 1
        if park[0] == "W":
            if park[-1]==park[1]:
                frag2 = 1
                
    if frag2 == 1:
        if b[-1]=="o":
            if park[-1] == "S":
                if park[0]==park[-2]:
                    print (''.join(park))
                    frag = 1
                    break
            if park[-1] == "W":
                if park[0]!=park[-2]:
                    print (''.join(park))
                    frag = 1
                    break
        if b[-1]=="x":
            if park[-1] == "S":
                if park[0]!=park[-2]:
                    print (''.join(park))
                    frag = 1
                    break
            if park[-1] == "W":
                if park[0]==park[-2]:
                    print (''.join(park))
                    frag = 1
                    break
if frag == 0:
    print(-1)