Buggy python submission (verdict: Time Limit Exceeded):
import sys
from io import StringIO
import unittest

def resolve():
    n = int(input())
    s = input()
    ans = 0
    r_cnt = s.count('R')
    g_cnt = s.count('G')
    g_cnt = s.count('G')

    for i in range(n):
        for j in range(1, n - i, 1):
            if s[i] != s[i+j]:
                for x in ('R', 'G', 'B'):
                    if x not in (s[i], s[i+j]):
                        tmp = x
                if i+2*j < n and s[i+2*j] == tmp:
                    ans += s[i+j+1:].count(tmp) - 1
                else:
                    ans += s[i+j+1:].count(tmp)

    print(ans)


class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)
    def test_入力例_1(self):
        input = """4
RRGB"""
        output = """1"""
        self.assertIO(input, output)
    def test_入力例_2(self):
        input = """39
RBRBGRBGGBBRRGBBRRRBGGBRBGBRBGBRBBBGBBB"""
        output = """1800"""
        self.assertIO(input, output)

if __name__ == "__main__":
    #unittest.main()
    resolve()


Fixed submission:
import sys
from io import StringIO
import unittest

def resolve():
    n = int(input())
    s = input()
    ans = s.count('R') * s.count('G') * s.count('B')

    for i in range(n):
        for j in range(1, (n - 1)//2 + 1, 1):
            if i + 2 * j < n:
                if s[i] != s[i + j] and s[i] != s[i + 2 * j] and s[i + j] != s[i + 2 * j]:
                    ans -= 1

    print(ans)


class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)
    def test_入力例_1(self):
        input = """4
RRGB"""
        output = """1"""
        self.assertIO(input, output)
    def test_入力例_2(self):
        input = """39
RBRBGRBGGBBRRGBBRRRBGGBRBGBRBGBRBBBGBBB"""
        output = """1800"""
        self.assertIO(input, output)

if __name__ == "__main__":
    #unittest.main()
    resolve()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from io import StringIO
import unittest

def resolve():
    n = int(input())
    s = input()
    ans = s.count('R') * s.count('G') * s.count('B')

    for i in range(n):
        for j in range(1, n, 1):
            if i + 2 * j < n:
                if s[i] != s[i + j] and s[i] != s[i + 2 * j] and s[i + j] != s[i + 2 * j]:
                    ans -= 1

    print(ans)


class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)
    def test_入力例_1(self):
        input = """4
RRGB"""
        output = """1"""
        self.assertIO(input, output)
    def test_入力例_2(self):
        input = """39
RBRBGRBGGBBRRGBBRRRBGGBRBGBRBGBRBBBGBBB"""
        output = """1800"""
        self.assertIO(input, output)

if __name__ == "__main__":
    # unittest.main()
    resolve()

Fixed submission:
import sys
from io import StringIO
import unittest

def resolve():
    n = int(input())
    s = input()
    ans = s.count('R') * s.count('G') * s.count('B')

    for i in range(n):
        for j in range(1, (n - 1)//2 + 1, 1):
            if i + 2 * j < n:
                if s[i] != s[i + j] and s[i] != s[i + 2 * j] and s[i + j] != s[i + 2 * j]:
                    ans -= 1

    print(ans)


class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)
    def test_入力例_1(self):
        input = """4
RRGB"""
        output = """1"""
        self.assertIO(input, output)
    def test_入力例_2(self):
        input = """39
RBRBGRBGGBBRRGBBRRRBGGBRBGBRBGBRBBBGBBB"""
        output = """1800"""
        self.assertIO(input, output)

if __name__ == "__main__":
    #unittest.main()
    resolve()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from io import StringIO
import unittest

def resolve():
    n = int(input())
    s = input()
    ans = 0
    r_cnt = s.count('R')
    g_cnt = s.count('G')
    g_cnt = s.count('G')

    for i in range(n):
        for j in range(1, n - i, 1):
            if s[i] != s[i+j]:
                for x in ('R', 'G', 'B'):
                    if x not in (s[i], s[i+j]):
                        tmp = x
                if i+2*j < n and s[i+2*j] == tmp:
                    ans += s[i+j+1:].count(tmp) - 1
                else:
                    ans += s[i+j+1:].count(tmp)

    print(ans)


class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)
    def test_入力例_1(self):
        input = """4
RRGB"""
        output = """1"""
        self.assertIO(input, output)
    def test_入力例_2(self):
        input = """39
RBRBGRBGGBBRRGBBRRRBGGBRBGBRBGBRBBBGBBB"""
        output = """1800"""
        self.assertIO(input, output)

if __name__ == "__main__":
    #unittest.main()
    resolve()

Fixed submission:
import sys
from io import StringIO
import unittest

def resolve():
    n = int(input())
    s = input()
    ans = s.count('R') * s.count('G') * s.count('B')

    for i in range(n):
        for j in range(1, (n - 1)//2 + 1, 1):
            if i + 2 * j < n:
                if s[i] != s[i + j] and s[i] != s[i + 2 * j] and s[i + j] != s[i + 2 * j]:
                    ans -= 1

    print(ans)


class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)
    def test_入力例_1(self):
        input = """4
RRGB"""
        output = """1"""
        self.assertIO(input, output)
    def test_入力例_2(self):
        input = """39
RBRBGRBGGBBRRGBBRRRBGGBRBGBRBGBRBBBGBBB"""
        output = """1800"""
        self.assertIO(input, output)

if __name__ == "__main__":
    #unittest.main()
    resolve()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from io import StringIO
import unittest

def resolve():
    n = int(input())
    s = input()
    ans = 0

    # for i in range(n):
    #     for j in range(1, n - i, 1):
    #         for k in range(1, n - i - j, 1):
    #             if j != k and s[i] != s[i+j] and s[i+j] != s[i+j+k] and s[i] != s[i+j+k]:
    #                 ans += 1

    for i in range(n):
        for j in range(1, n - i, 1):
            if s[i] != s[i+j]:
                for x in ('R', 'G', 'B'):
                    if x not in (s[i], s[i+j]):
                        tmp = x
                ans += s[i+2*j+1:].count(tmp) + s[i+j+1:i+2*j].count(tmp)

    print(ans)


class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)
    def test_入力例_1(self):
        input = """4
RRGB"""
        output = """1"""
        self.assertIO(input, output)
    def test_入力例_2(self):
        input = """39
RBRBGRBGGBBRRGBBRRRBGGBRBGBRBGBRBBBGBBB"""
        output = """1800"""
        self.assertIO(input, output)

if __name__ == "__main__":
    #unittest.main()
    resolve()

Fixed submission:
import sys
from io import StringIO
import unittest

def resolve():
    n = int(input())
    s = input()
    ans = s.count('R') * s.count('G') * s.count('B')

    for i in range(n):
        for j in range(1, (n - 1)//2 + 1, 1):
            if i + 2 * j < n:
                if s[i] != s[i + j] and s[i] != s[i + 2 * j] and s[i + j] != s[i + 2 * j]:
                    ans -= 1

    print(ans)


class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)
    def test_入力例_1(self):
        input = """4
RRGB"""
        output = """1"""
        self.assertIO(input, output)
    def test_入力例_2(self):
        input = """39
RBRBGRBGGBBRRGBBRRRBGGBRBGBRBGBRBBBGBBB"""
        output = """1800"""
        self.assertIO(input, output)

if __name__ == "__main__":
    #unittest.main()
    resolve()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from io import StringIO
import unittest

def resolve():
    n = int(input())
    s = input()
    ans = 0

    for i in range(n):
        for j in range(1, n - i, 1):
            for k in range(1, n - i - j, 1):
                if j != k and s[i] != s[i+j] and s[i+j] != s[i+j+k] and s[i] != s[i+j+k]:
                    ans += 1

    print(ans)


class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)
    def test_入力例_1(self):
        input = """4
RRGB"""
        output = """1"""
        self.assertIO(input, output)
    def test_入力例_2(self):
        input = """39
RBRBGRBGGBBRRGBBRRRBGGBRBGBRBGBRBBBGBBB"""
        output = """1800"""
        self.assertIO(input, output)

if __name__ == "__main__":
    # unittest.main()
    resolve()

Fixed submission:
import sys
from io import StringIO
import unittest

def resolve():
    n = int(input())
    s = input()
    ans = s.count('R') * s.count('G') * s.count('B')

    for i in range(n):
        for j in range(1, (n - 1)//2 + 1, 1):
            if i + 2 * j < n:
                if s[i] != s[i + j] and s[i] != s[i + 2 * j] and s[i + j] != s[i + 2 * j]:
                    ans -= 1

    print(ans)


class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)
    def test_入力例_1(self):
        input = """4
RRGB"""
        output = """1"""
        self.assertIO(input, output)
    def test_入力例_2(self):
        input = """39
RBRBGRBGGBBRRGBBRRRBGGBRBGBRBGBRBBBGBBB"""
        output = """1800"""
        self.assertIO(input, output)

if __name__ == "__main__":
    #unittest.main()
    resolve()