Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
S = input()

R_lst = [0] * N
G_lst = [0] * N
B_lst = [0] * N

r_cnt = 0
g_cnt = 0
b_cnt = 0

cnt = 0
for i in range(N):
    a = S[i]

    if a == 'R':
        r_cnt += 1
    elif a == 'G':
        g_cnt += 1
    else:
        b_cnt += 1

    R_lst[i] = r_cnt
    G_lst[i] = g_cnt
    B_lst[i] = b_cnt

    for j in range(i):
        b = S[j]

        d = i - j
        if (a == 'R' and b == 'G') or (a == 'G' and b == 'R'):
            if j - 1 >=0 and B_lst[j - 1] > 0:
                cnt += B_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'B':
                    cnt -= 1

        elif (a == 'G' and b == 'B') or (a == 'B' and b == 'G'):
            if j - 1 >=0 and R_lst[j - 1] > 0:
                cnt += R_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'R':
                    cnt -= 1

        elif (a == 'B' and b == 'R') or (a == 'R' and b == 'B'):
            if j - 1 >= 0 and G_lst[j - 1] > 0:
                cnt += G_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'G':
                    cnt -= 1

print(cnt)

Fixed submission:
N = int(input())
S = input()

diff_dic = {}
diff_dic[('R', 'G')] = []
diff_dic[('R', 'B')] = []
diff_dic[('G', 'R')] = []
diff_dic[('G', 'B')] = []
diff_dic[('B', 'G')] = []
diff_dic[('B', 'R')] = []

R_lst = [0] * N
G_lst = [0] * N
B_lst = [0] * N

r_cnt = 0
g_cnt = 0
b_cnt = 0

cnt = 0
for i in range(N):
    if S[i] == 'R':
        r_cnt += 1
    elif S[i] == 'G':
        g_cnt += 1
    else:
        b_cnt += 1

    R_lst[i] = r_cnt
    G_lst[i] = g_cnt
    B_lst[i] = b_cnt

    for j in range(i):
        d = i - j
        if (S[i] == 'R' and S[j] == 'G') or (S[i] == 'G' and S[j] == 'R'):
            if j - 1 >=0 and B_lst[j - 1] > 0:
                cnt += B_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'B':
                    cnt -= 1

        if (S[i] == 'G' and S[j] == 'B') or (S[i] == 'B' and S[j] == 'G'):
            if j - 1 >=0 and R_lst[j - 1] > 0:
                cnt += R_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'R':
                    cnt -= 1

        if (S[i] == 'B' and S[j] == 'R') or (S[i] == 'R' and S[j] == 'B'):
            if j - 1 >= 0 and G_lst[j - 1] > 0:
                cnt += G_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'G':
                    cnt -= 1

print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
S = input()

R_lst = [0] * N
G_lst = [0] * N
B_lst = [0] * N

r_cnt = 0
g_cnt = 0
b_cnt = 0

cnt = 0
for i in range(N):
    a = S[i]

    if a == 'R':
        r_cnt += 1
    elif a == 'G':
        g_cnt += 1
    else:
        b_cnt += 1

    R_lst[i] = r_cnt
    G_lst[i] = g_cnt
    B_lst[i] = b_cnt

    for j in range(i):
        b = S[j]

        d = i - j
        if (a == 'R' and b == 'G') or (a == 'G' and b == 'R'):
            if j - 1 >=0 and B_lst[j - 1] > 0:
                cnt += B_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'B':
                    cnt -= 1

        if (a == 'G' and b == 'B') or (a == 'B' and b == 'G'):
            if j - 1 >=0 and R_lst[j - 1] > 0:
                cnt += R_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'R':
                    cnt -= 1

        if (a == 'B' and b == 'R') or (a == 'R' and b == 'B'):
            if j - 1 >= 0 and G_lst[j - 1] > 0:
                cnt += G_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'G':
                    cnt -= 1

print(cnt)


Fixed submission:
N = int(input())
S = input()

diff_dic = {}
diff_dic[('R', 'G')] = []
diff_dic[('R', 'B')] = []
diff_dic[('G', 'R')] = []
diff_dic[('G', 'B')] = []
diff_dic[('B', 'G')] = []
diff_dic[('B', 'R')] = []

R_lst = [0] * N
G_lst = [0] * N
B_lst = [0] * N

r_cnt = 0
g_cnt = 0
b_cnt = 0

cnt = 0
for i in range(N):
    if S[i] == 'R':
        r_cnt += 1
    elif S[i] == 'G':
        g_cnt += 1
    else:
        b_cnt += 1

    R_lst[i] = r_cnt
    G_lst[i] = g_cnt
    B_lst[i] = b_cnt

    for j in range(i):
        d = i - j
        if (S[i] == 'R' and S[j] == 'G') or (S[i] == 'G' and S[j] == 'R'):
            if j - 1 >=0 and B_lst[j - 1] > 0:
                cnt += B_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'B':
                    cnt -= 1

        if (S[i] == 'G' and S[j] == 'B') or (S[i] == 'B' and S[j] == 'G'):
            if j - 1 >=0 and R_lst[j - 1] > 0:
                cnt += R_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'R':
                    cnt -= 1

        if (S[i] == 'B' and S[j] == 'R') or (S[i] == 'R' and S[j] == 'B'):
            if j - 1 >= 0 and G_lst[j - 1] > 0:
                cnt += G_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'G':
                    cnt -= 1

print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
S = input()

diff_dic = {}
diff_dic[('R', 'G')] = []
diff_dic[('R', 'B')] = []
diff_dic[('G', 'R')] = []
diff_dic[('G', 'B')] = []
diff_dic[('B', 'G')] = []
diff_dic[('B', 'R')] = []

R_lst = [0] * N
G_lst = [0] * N
B_lst = [0] * N

r_cnt = 0
g_cnt = 0
b_cnt = 0

cnt = 0
for i in range(N):
    if S[i] == 'R':
        r_cnt += 1
    elif S[i] == 'G':
        g_cnt += 1
    else:
        b_cnt += 1

    R_lst[i] = r_cnt
    G_lst[i] = g_cnt
    B_lst[i] = b_cnt

    for j in range(i):
        d = i - j
        if (S[i] == 'R' and S[j] == 'G') or (S[i] == 'G' and S[j] == 'R'):
            if j - 1 >=0 and B_lst[j - 1] > 0:
                cnt += B_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'B':
                    cnt -= 1

        if (S[i] == 'G' and S[j] == 'B') or (S[i] == 'B' and S[j] == 'G'):
            if j - 1 >=0 and R_lst[j - 1] > 0:
                cnt += R_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'R':
                    cnt -= 1

        if (S[i] == 'B' and S[j] == 'R') or (S[i] == 'R' and S[j] == 'B'):
            if j - 1 >= 0 and G_lst[j - 1] > 0:
                cnt += G_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'G':
                    cnt -= 1

print(cnt)


Fixed submission:
N = int(input())
S = input()

diff_dic = {}
diff_dic[('R', 'G')] = []
diff_dic[('R', 'B')] = []
diff_dic[('G', 'R')] = []
diff_dic[('G', 'B')] = []
diff_dic[('B', 'G')] = []
diff_dic[('B', 'R')] = []

R_lst = [0] * N
G_lst = [0] * N
B_lst = [0] * N

r_cnt = 0
g_cnt = 0
b_cnt = 0

cnt = 0
for i in range(N):
    if S[i] == 'R':
        r_cnt += 1
    elif S[i] == 'G':
        g_cnt += 1
    else:
        b_cnt += 1

    R_lst[i] = r_cnt
    G_lst[i] = g_cnt
    B_lst[i] = b_cnt

    for j in range(i):
        d = i - j
        if (S[i] == 'R' and S[j] == 'G') or (S[i] == 'G' and S[j] == 'R'):
            if j - 1 >=0 and B_lst[j - 1] > 0:
                cnt += B_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'B':
                    cnt -= 1

        if (S[i] == 'G' and S[j] == 'B') or (S[i] == 'B' and S[j] == 'G'):
            if j - 1 >=0 and R_lst[j - 1] > 0:
                cnt += R_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'R':
                    cnt -= 1

        if (S[i] == 'B' and S[j] == 'R') or (S[i] == 'R' and S[j] == 'B'):
            if j - 1 >= 0 and G_lst[j - 1] > 0:
                cnt += G_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'G':
                    cnt -= 1

print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
S = input()

diff_dic = {}
diff_dic[('R', 'G')] = []
diff_dic[('R', 'B')] = []
diff_dic[('G', 'R')] = []
diff_dic[('G', 'B')] = []
diff_dic[('B', 'G')] = []
diff_dic[('B', 'R')] = []

R_lst = [0] * N
G_lst = [0] * N
B_lst = [0] * N

r_cnt = 0
g_cnt = 0
b_cnt = 0

cnt = 0
for i in range(N):
    if S[i] == 'R':
        r_cnt += 1
    elif S[i] == 'G':
        g_cnt += 1
    else:
        b_cnt += 1

    R_lst[i] = r_cnt
    G_lst[i] = g_cnt
    B_lst[i] = b_cnt

    for j in range(i):
        d = i - j
        if (S[i] == 'R' and S[j] == 'G') or (S[i] == 'G' and S[j] == 'R'):
            if j - 1 >=0 and B_lst[j - 1] > 0:
                cnt += B_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'B':
                    cnt -= 1

        if (S[i] == 'G' and S[j] == 'B') or (S[i] == 'B' and S[j] == 'G'):
            if j - 1 >=0 and R_lst[j - 1] > 0:
                cnt += R_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'R':
                    cnt -= 1

        if (S[i] == 'B' and S[j] == 'R') or (S[i] == 'R' and S[j] == 'B'):
            if j - 1 >= 0 and G_lst[j - 1] > 0:
                cnt += G_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'G':
                    cnt -= 1

print(cnt)



Fixed submission:
N = int(input())
S = input()

diff_dic = {}
diff_dic[('R', 'G')] = []
diff_dic[('R', 'B')] = []
diff_dic[('G', 'R')] = []
diff_dic[('G', 'B')] = []
diff_dic[('B', 'G')] = []
diff_dic[('B', 'R')] = []

R_lst = [0] * N
G_lst = [0] * N
B_lst = [0] * N

r_cnt = 0
g_cnt = 0
b_cnt = 0

cnt = 0
for i in range(N):
    if S[i] == 'R':
        r_cnt += 1
    elif S[i] == 'G':
        g_cnt += 1
    else:
        b_cnt += 1

    R_lst[i] = r_cnt
    G_lst[i] = g_cnt
    B_lst[i] = b_cnt

    for j in range(i):
        d = i - j
        if (S[i] == 'R' and S[j] == 'G') or (S[i] == 'G' and S[j] == 'R'):
            if j - 1 >=0 and B_lst[j - 1] > 0:
                cnt += B_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'B':
                    cnt -= 1

        if (S[i] == 'G' and S[j] == 'B') or (S[i] == 'B' and S[j] == 'G'):
            if j - 1 >=0 and R_lst[j - 1] > 0:
                cnt += R_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'R':
                    cnt -= 1

        if (S[i] == 'B' and S[j] == 'R') or (S[i] == 'R' and S[j] == 'B'):
            if j - 1 >= 0 and G_lst[j - 1] > 0:
                cnt += G_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'G':
                    cnt -= 1

print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
S = input()

diff_dic = {}
diff_dic[('R', 'G')] = []
diff_dic[('R', 'B')] = []
diff_dic[('G', 'R')] = []
diff_dic[('G', 'B')] = []
diff_dic[('B', 'G')] = []
diff_dic[('B', 'R')] = []

R_lst = [0] * N
G_lst = [0] * N
B_lst = [0] * N

r_cnt = 0
g_cnt = 0
b_cnt = 0
for i in range(N):
    if S[i] == 'R':
        r_cnt += 1
    elif S[i] == 'G':
        g_cnt += 1
    else:
        b_cnt += 1

    R_lst[i] = r_cnt
    G_lst[i] = g_cnt
    B_lst[i] = b_cnt

    for j in range(i + 1, N):
        if S[i] == 'R':
            if S[j] != 'R':
                diff_dic[('R', S[j])].append((j, j - i))

        elif S[i] == 'G':
            if S[j] != 'G':
                diff_dic[('G', S[j])].append((j, j - i))

        elif S[i] == 'B':
            if S[j] != 'B':
                diff_dic[('B', S[j])].append((j, j - i))


cnt = 0

for t in [('R', 'G'), ('G', 'R')]:
    for j, d in diff_dic[t]:
        if j < N - 1:
            if b_cnt - B_lst[j] > 0:
                cnt += b_cnt - B_lst[j]
                if j + d < N and S[j + d] == 'B':
                    cnt -= 1

for t in [('G', 'B'), ('B', 'G')]:
    for j, d in diff_dic[t]:
        if j < N - 1:
            if r_cnt - R_lst[j] > 0:
                cnt += r_cnt - R_lst[j]
                if j + d < N and S[j + d] == 'R':
                    cnt -= 1

for t in [('B', 'R'), ('R', 'B')]:
    for j, d in diff_dic[t]:
        if j < N - 1:
            if g_cnt - G_lst[j] > 0:
                cnt += g_cnt - G_lst[j]
                if j + d < N and S[j + d] == 'G':
                    cnt -= 1

print(cnt)


Fixed submission:
N = int(input())
S = input()

diff_dic = {}
diff_dic[('R', 'G')] = []
diff_dic[('R', 'B')] = []
diff_dic[('G', 'R')] = []
diff_dic[('G', 'B')] = []
diff_dic[('B', 'G')] = []
diff_dic[('B', 'R')] = []

R_lst = [0] * N
G_lst = [0] * N
B_lst = [0] * N

r_cnt = 0
g_cnt = 0
b_cnt = 0

cnt = 0
for i in range(N):
    if S[i] == 'R':
        r_cnt += 1
    elif S[i] == 'G':
        g_cnt += 1
    else:
        b_cnt += 1

    R_lst[i] = r_cnt
    G_lst[i] = g_cnt
    B_lst[i] = b_cnt

    for j in range(i):
        d = i - j
        if (S[i] == 'R' and S[j] == 'G') or (S[i] == 'G' and S[j] == 'R'):
            if j - 1 >=0 and B_lst[j - 1] > 0:
                cnt += B_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'B':
                    cnt -= 1

        if (S[i] == 'G' and S[j] == 'B') or (S[i] == 'B' and S[j] == 'G'):
            if j - 1 >=0 and R_lst[j - 1] > 0:
                cnt += R_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'R':
                    cnt -= 1

        if (S[i] == 'B' and S[j] == 'R') or (S[i] == 'R' and S[j] == 'B'):
            if j - 1 >= 0 and G_lst[j - 1] > 0:
                cnt += G_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'G':
                    cnt -= 1

print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
S = input()

diff_dic = {}
diff_dic[('R', 'G')] = []
diff_dic[('R', 'B')] = []
diff_dic[('G', 'R')] = []
diff_dic[('G', 'B')] = []
diff_dic[('B', 'G')] = []
diff_dic[('B', 'R')] = []

for i in range(N):
    for j in range(i + 1, N):

        if S[i] == 'R':
            if S[j] != 'R':
                diff_dic[('R', S[j])].append((i, j - i))

        if S[i] == 'G':
            if S[j] != 'G':
                diff_dic[('G', S[j])].append((i, j - i))

        if S[i] == 'B':
            if S[j] != 'B':
                diff_dic[('B', S[j])].append((i, j - i))

cnt = 0
for i in range(N):
    if S[i] == 'R':
        for j, d in diff_dic[('G', 'B')]:
            if j > i and (j - i) != d:
                cnt += 1

        for j, d in diff_dic[('B', 'G')]:
            if j > i and (j - i) != d:
                cnt += 1

    if S[i] == 'G':
        for j, d in diff_dic[('R', 'B')]:
            if j > i and (j - i) != d:
                cnt += 1

        for j, d in diff_dic[('B', 'R')]:
            if j > i and (j - i) != d:
                cnt += 1

    if S[i] == 'B':
        for j, d in diff_dic[('R', 'G')]:
            if j > i and (j - i) != d:
                cnt += 1

        for j, d in diff_dic[('G', 'R')]:
            if j > i and (j - i) != d:
                cnt += 1

print(cnt)


Fixed submission:
N = int(input())
S = input()

diff_dic = {}
diff_dic[('R', 'G')] = []
diff_dic[('R', 'B')] = []
diff_dic[('G', 'R')] = []
diff_dic[('G', 'B')] = []
diff_dic[('B', 'G')] = []
diff_dic[('B', 'R')] = []

R_lst = [0] * N
G_lst = [0] * N
B_lst = [0] * N

r_cnt = 0
g_cnt = 0
b_cnt = 0

cnt = 0
for i in range(N):
    if S[i] == 'R':
        r_cnt += 1
    elif S[i] == 'G':
        g_cnt += 1
    else:
        b_cnt += 1

    R_lst[i] = r_cnt
    G_lst[i] = g_cnt
    B_lst[i] = b_cnt

    for j in range(i):
        d = i - j
        if (S[i] == 'R' and S[j] == 'G') or (S[i] == 'G' and S[j] == 'R'):
            if j - 1 >=0 and B_lst[j - 1] > 0:
                cnt += B_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'B':
                    cnt -= 1

        if (S[i] == 'G' and S[j] == 'B') or (S[i] == 'B' and S[j] == 'G'):
            if j - 1 >=0 and R_lst[j - 1] > 0:
                cnt += R_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'R':
                    cnt -= 1

        if (S[i] == 'B' and S[j] == 'R') or (S[i] == 'R' and S[j] == 'B'):
            if j - 1 >= 0 and G_lst[j - 1] > 0:
                cnt += G_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'G':
                    cnt -= 1

print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
S = input()

diff_dic = {}

diff_dic[('R', 'G')] = []
diff_dic[('R', 'B')] = []
diff_dic[('G', 'R')] = []
diff_dic[('G', 'B')] = []
diff_dic[('B', 'G')] = []
diff_dic[('B', 'R')] = []

for i in range(N):
    for j in range(i + 1, N):

        if S[i] == 'R':
            if S[j] != 'R':
                diff_dic[('R', S[j])].append((i, j - i))

        if S[i] == 'G':
            if S[j] != 'G':
                diff_dic[('G', S[j])].append((i, j - i))

        if S[i] == 'B':
            if S[j] != 'B':
                diff_dic[('B', S[j])].append((i, j - i))

cnt = 0
for i in range(N):
    if S[i] == 'R':
        for j, d in diff_dic[('G', 'B')]:
            if j > i and (j - i) != d:
                cnt += 1

        for j, d in diff_dic[('B', 'G')]:
            if j > i and (j - i) != d:
                cnt += 1

    if S[i] == 'G':
        for j, d in diff_dic[('R', 'B')]:
            if j > i and (j - i) != d:
                cnt += 1

        for j, d in diff_dic[('B', 'R')]:
            if j > i and (j - i) != d:
                cnt += 1

    if S[i] == 'B':
        for j, d in diff_dic[('R', 'G')]:
            if j > i and (j - i) != d:
                cnt += 1

        for j, d in diff_dic[('G', 'R')]:
            if j > i and (j - i) != d:
                cnt += 1

print(cnt)


Fixed submission:
N = int(input())
S = input()

diff_dic = {}
diff_dic[('R', 'G')] = []
diff_dic[('R', 'B')] = []
diff_dic[('G', 'R')] = []
diff_dic[('G', 'B')] = []
diff_dic[('B', 'G')] = []
diff_dic[('B', 'R')] = []

R_lst = [0] * N
G_lst = [0] * N
B_lst = [0] * N

r_cnt = 0
g_cnt = 0
b_cnt = 0

cnt = 0
for i in range(N):
    if S[i] == 'R':
        r_cnt += 1
    elif S[i] == 'G':
        g_cnt += 1
    else:
        b_cnt += 1

    R_lst[i] = r_cnt
    G_lst[i] = g_cnt
    B_lst[i] = b_cnt

    for j in range(i):
        d = i - j
        if (S[i] == 'R' and S[j] == 'G') or (S[i] == 'G' and S[j] == 'R'):
            if j - 1 >=0 and B_lst[j - 1] > 0:
                cnt += B_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'B':
                    cnt -= 1

        if (S[i] == 'G' and S[j] == 'B') or (S[i] == 'B' and S[j] == 'G'):
            if j - 1 >=0 and R_lst[j - 1] > 0:
                cnt += R_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'R':
                    cnt -= 1

        if (S[i] == 'B' and S[j] == 'R') or (S[i] == 'R' and S[j] == 'B'):
            if j - 1 >= 0 and G_lst[j - 1] > 0:
                cnt += G_lst[j - 1]
                if j - d >= 0 and S[j - d] == 'G':
                    cnt -= 1

print(cnt)