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):
N = int(input())

s = input()

ans_first = ["SS", "SW", "WS", "WW"]

cand_oo = ["SSSS", "SWWS", "WWSW", "WSWW"]
cand_ox = ["SSSW", "SWWW", "WWSS", "SSWS"]
cand_xo = ["WSSS", "WWWS", "SWSW", "SSWW"]
cand_xx = ["WSSW", "WWWW", "SWSS", "WSWS"]

answered = False

for a in ans_first:
    for i in range(1, N-1):
        if (s[i] == "o" and a[i] == "S") or (s[i] == "x" and a[i] == "W"):
            a = a + a[i-1]
            
        elif (s[i] == "o" and a[i] == "W") or (s[i] == "x" and a[i] == "S") :
            if a[i-1] == "S":
                a = a + "W"
            else:
                a = a + "S"
            
    if s[-1] + s[0] == "oo": 
        for can in cand_oo:
            if can == a[-2:] + a[:2]:
                print(a)
                break
                
    elif s[-1] + s[0] == "ox": 
        for can in cand_ox:
            if can == a[-2:] + a[:2]:
                print(a)
                break
    
    elif s[-1] + s[0] == "xo": 
        for can in cand_xo:
            if can == a[-2:] + a[:2]:
                print(a)
                break
    
    elif s[-1] + s[0] == "xx": 
        for can in cand_xx:
            if can == a[-2:] + a[:2]:
                print(a)
                break
                
if answered == False:
    print(-1)

Fixed, accepted submission:
N = int(input())

s = input()

ans_first = ["SS", "SW", "WS", "WW"]

cand_oo = ["SSSS", "SWWS", "WWSW", "WSWW"]
cand_ox = ["SSSW", "SWWW", "WWSS", "SSWS"]
cand_xo = ["WSSS", "WWWS", "SWSW", "SSWW"]
cand_xx = ["WSSW", "WWWW", "SWSS", "WSWS"]

answered = False

for a in ans_first:
    if answered == True:
        break
        
        
    for i in range(1, N-1):
        if (s[i] == "o" and a[i] == "S") or (s[i] == "x" and a[i] == "W"):
            a = a + a[i-1]
            
        elif (s[i] == "o" and a[i] == "W") or (s[i] == "x" and a[i] == "S") :
            if a[i-1] == "S":
                a = a + "W"
            else:
                a = a + "S"
            
    if s[-1] + s[0] == "oo": 
        for can in cand_oo:
            if can == a[-2:] + a[:2]:
                print(a)
                answered = True
                break
                
    elif s[-1] + s[0] == "ox": 
        for can in cand_ox:
            if can == a[-2:] + a[:2]:
                print(a)
                answered = True
                break
    
    elif s[-1] + s[0] == "xo": 
        for can in cand_xo:
            if can == a[-2:] + a[:2]:
                print(a)
                answered = True
                break
    
    elif s[-1] + s[0] == "xx": 
        for can in cand_xx:
            if can == a[-2:] + a[:2]:
                print(a)
                answered = True
                break
                
if answered == False:
    print(-1)