Buggy python submission (verdict: Runtime Error):
N = int(input())
S = input()
result = 0
'''
for i in range(N):
    print(result)
    for j in range(i+1,N):
        if S[i] != S[j]:
            for k in range(j ,N):
                if k- j == j - i:
                    continue
                if S[j] != S[k] and S[i] != S[k]:
                    result +=1
print(result)
'''
r = S.count('R')
g = S.count('G')
b = S.count('B')
target = set('RGB')
result = r * g * b
for i in range(N):
    for j in range(1, min(i, (N - i + 1)) + 1):
        if target == set(S[i] + S[i-j] + S[j + i]):
            result -= 1
print(result)

Fixed submission:
N = int(input())
S = input()
result = 0
'''
for i in range(N):
    print(result)
    for j in range(i+1,N):
        if S[i] != S[j]:
            for k in range(j ,N):
                if k- j == j - i:
                    continue
                if S[j] != S[k] and S[i] != S[k]:
                    result +=1
print(result)
'''
r = S.count('R')
g = S.count('G')
b = S.count('B')
target = set('RGB')
result = r * g * b
for i in range(N):
    for j in range(1, min(i, (N - i - 1)) + 1):
        if target == set(S[i] + S[i-j] + S[j + i]):
            result -= 1
print(result)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
S = input()
result = 0
'''
for i in range(N):
    print(result)
    for j in range(i+1,N):
        if S[i] != S[j]:
            for k in range(j ,N):
                if k- j == j - i:
                    continue
                if S[j] != S[k] and S[i] != S[k]:
                    result +=1
print(result)
'''
r = S.count('R')
g = S.count('G')
b = S.count('B')
target = set('RGB')
result = r*g*b
for i in range(N):
    for j in range(i + 1, N):
        if S[i] != S[j]:
            tmp = (target - set(S[i]+S[j])).pop()
            if 2*j-i < N and S[2 * j - i] == tmp:
                result -= 1
print(result)

Fixed submission:
N = int(input())
S = input()
result = 0
'''
for i in range(N):
    print(result)
    for j in range(i+1,N):
        if S[i] != S[j]:
            for k in range(j ,N):
                if k- j == j - i:
                    continue
                if S[j] != S[k] and S[i] != S[k]:
                    result +=1
print(result)
'''
r = S.count('R')
g = S.count('G')
b = S.count('B')
target = set('RGB')
result = r * g * b
for i in range(N):
    for j in range(1, min(i, (N - i - 1)) + 1):
        if target == set(S[i] + S[i-j] + S[j + i]):
            result -= 1
print(result)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
S = input()
result = 0
'''
for i in range(N):
    print(result)
    for j in range(i+1,N):
        if S[i] != S[j]:
            for k in range(j ,N):
                if k- j == j - i:
                    continue
                if S[j] != S[k] and S[i] != S[k]:
                    result +=1
print(result)
'''

target = set('RGB')
for i in range(N):
    #print(result)
    for j in range(i + 1, N):
        if S[i] != S[j]:
            tmp = (target - set(S[i]+S[j])).pop()
            result += S.count(tmp, j + 1, N)
            if 2*j-i < N and S[2 * j - i] == tmp:
                result -= 1
print(result)

Fixed submission:
N = int(input())
S = input()
result = 0
'''
for i in range(N):
    print(result)
    for j in range(i+1,N):
        if S[i] != S[j]:
            for k in range(j ,N):
                if k- j == j - i:
                    continue
                if S[j] != S[k] and S[i] != S[k]:
                    result +=1
print(result)
'''
r = S.count('R')
g = S.count('G')
b = S.count('B')
target = set('RGB')
result = r * g * b
for i in range(N):
    for j in range(1, min(i, (N - i - 1)) + 1):
        if target == set(S[i] + S[i-j] + S[j + i]):
            result -= 1
print(result)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
S = input()
result = 0
'''
for i in range(N):
    print(result)
    for j in range(i+1,N):
        if S[i] != S[j]:
            for k in range(j ,N):
                if k- j == j - i:
                    continue
                if S[j] != S[k] and S[i] != S[k]:
                    result +=1
print(result)
'''
for i in range(N):
    #print(result)
    for j in range(i + 1, N):
        if S[i] != S[j]:
            target = 'RGB'.strip(S[i]) if S[i] != 'G' else 'RB'
            target = target.strip(S[j])
            result += S.count(target, j + 1, N)
            if 2*j-i < N and S[2 * j - i] == target:
                result -= 1
print(result)


Fixed submission:
N = int(input())
S = input()
result = 0
'''
for i in range(N):
    print(result)
    for j in range(i+1,N):
        if S[i] != S[j]:
            for k in range(j ,N):
                if k- j == j - i:
                    continue
                if S[j] != S[k] and S[i] != S[k]:
                    result +=1
print(result)
'''
r = S.count('R')
g = S.count('G')
b = S.count('B')
target = set('RGB')
result = r * g * b
for i in range(N):
    for j in range(1, min(i, (N - i - 1)) + 1):
        if target == set(S[i] + S[i-j] + S[j + i]):
            result -= 1
print(result)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
S = input()
result = 0
for i in range(N):
    for j in range(i+1,N):
        if S[i] != S[j]:
            for k in range(j ,N):
                if k- j == j - i:
                    continue
                if S[j] != S[k] and S[i] != S[k]:
                    result +=1
print(result)

Fixed submission:
N = int(input())
S = input()
result = 0
'''
for i in range(N):
    print(result)
    for j in range(i+1,N):
        if S[i] != S[j]:
            for k in range(j ,N):
                if k- j == j - i:
                    continue
                if S[j] != S[k] and S[i] != S[k]:
                    result +=1
print(result)
'''
r = S.count('R')
g = S.count('G')
b = S.count('B')
target = set('RGB')
result = r * g * b
for i in range(N):
    for j in range(1, min(i, (N - i - 1)) + 1):
        if target == set(S[i] + S[i-j] + S[j + i]):
            result -= 1
print(result)