Buggy python submission (verdict: Runtime Error):
import collections
n = int(input())
s = list(input())
a = collections.Counter(s)
a = list(a.items())
ans = 0
# ar = []
# for i in range(1,2000):
#     c_ar = []
#     for j in range(1,n+1,i):
#         c_ar.append(j)
#     if len(c_ar) >= 3:
#         ar.append(c_ar)
# print(ar)
# print(len(ar))
# for i in range(len(ar)):
#     print(ar[i])
#     print(len(ar[i]))
#     for j in range(len(ar[i])-2):
#         print(s[ar[i][j]-1],s[ar[i][j+1]-1],s[ar[i][j+2]-1])
#         print(ar[i][j]-1, ar[i][j+1]-1, ar[i][j+2]-1)
#         if s[ar[i][j]-1] != s[ar[i][j+1]-1] and s[ar[i][j+1]-1] != s[ar[i][j+2]-1] and s[ar[i][j+2]-1] != s[ar[i][j]-1]:
#             cnt += 1
#             print("Y")
#     print(cnt)
# print(a[0][1],a[1][1],a[2][1])
# print(a[0][1]*a[1][1]*a[2][1]-cnt)
if n == 1 or n == 2 or n == 3:
    print(0)
    exit()
for i in range(1,n//2+3):
    cnt = 0
    #print(i)
    for j in range(n):
        if cnt + 2*i > n-1:
            break
        x,y,z = s[cnt], s[cnt+i], s[cnt+2*i]
        #print(cnt, cnt+i, cnt+i+i)
        if x != y and y != z and z != x:
            ans += 1
        cnt += 1
print(a[0][1]*a[1][1]*a[2][1]-ans)



Fixed submission:
import collections
n = int(input())
s = list(input())
a = collections.Counter(s)
a = list(a.items())
ans = 0
# ar = []
# for i in range(1,2000):
#     c_ar = []
#     for j in range(1,n+1,i):
#         c_ar.append(j)
#     if len(c_ar) >= 3:
#         ar.append(c_ar)
# print(ar)
# print(len(ar))
# for i in range(len(ar)):
#     print(ar[i])
#     print(len(ar[i]))
#     for j in range(len(ar[i])-2):
#         print(s[ar[i][j]-1],s[ar[i][j+1]-1],s[ar[i][j+2]-1])
#         print(ar[i][j]-1, ar[i][j+1]-1, ar[i][j+2]-1)
#         if s[ar[i][j]-1] != s[ar[i][j+1]-1] and s[ar[i][j+1]-1] != s[ar[i][j+2]-1] and s[ar[i][j+2]-1] != s[ar[i][j]-1]:
#             cnt += 1
#             print("Y")
#     print(cnt)
# print(a[0][1],a[1][1],a[2][1])
# print(a[0][1]*a[1][1]*a[2][1]-cnt)
if n == 1 or n == 2 or n == 3:
    print(0)
    exit()
if len(a) != 3:
    print(0)
    exit()
for i in range(1,n//2+3):
    cnt = 0
    #print(i)
    for j in range(n):
        if cnt + 2*i > n-1:
            break
        x,y,z = s[cnt], s[cnt+i], s[cnt+2*i]
        #print(cnt, cnt+i, cnt+i+i)
        if x != y and y != z and z != x:
            ans += 1
        cnt += 1
print(a[0][1]*a[1][1]*a[2][1]-ans)

Buggy python submission (verdict: Runtime Error):
import collections
n = int(input())
s = list(input())
a = collections.Counter(s)
a = list(a.items())
ans = 0
# ar = []
# for i in range(1,2000):
#     c_ar = []
#     for j in range(1,n+1,i):
#         c_ar.append(j)
#     if len(c_ar) >= 3:
#         ar.append(c_ar)
# print(ar)
# print(len(ar))
# for i in range(len(ar)):
#     print(ar[i])
#     print(len(ar[i]))
#     for j in range(len(ar[i])-2):
#         print(s[ar[i][j]-1],s[ar[i][j+1]-1],s[ar[i][j+2]-1])
#         print(ar[i][j]-1, ar[i][j+1]-1, ar[i][j+2]-1)
#         if s[ar[i][j]-1] != s[ar[i][j+1]-1] and s[ar[i][j+1]-1] != s[ar[i][j+2]-1] and s[ar[i][j+2]-1] != s[ar[i][j]-1]:
#             cnt += 1
#             print("Y")
#     print(cnt)
# print(a[0][1],a[1][1],a[2][1])
# print(a[0][1]*a[1][1]*a[2][1]-cnt)

for i in range(1,n//2+3):
    cnt = 0
    #print(i)
    for j in range(n):
        if cnt + 2*i > n-1:
            break
        x,y,z = s[cnt], s[cnt+i], s[cnt+2*i]
        #print(cnt, cnt+i, cnt+i+i)
        if x != y and y != z and z != x:
            ans += 1
        cnt += 1
print(a[0][1]*a[1][1]*a[2][1]-ans)



Fixed submission:
import collections
n = int(input())
s = list(input())
a = collections.Counter(s)
a = list(a.items())
ans = 0
# ar = []
# for i in range(1,2000):
#     c_ar = []
#     for j in range(1,n+1,i):
#         c_ar.append(j)
#     if len(c_ar) >= 3:
#         ar.append(c_ar)
# print(ar)
# print(len(ar))
# for i in range(len(ar)):
#     print(ar[i])
#     print(len(ar[i]))
#     for j in range(len(ar[i])-2):
#         print(s[ar[i][j]-1],s[ar[i][j+1]-1],s[ar[i][j+2]-1])
#         print(ar[i][j]-1, ar[i][j+1]-1, ar[i][j+2]-1)
#         if s[ar[i][j]-1] != s[ar[i][j+1]-1] and s[ar[i][j+1]-1] != s[ar[i][j+2]-1] and s[ar[i][j+2]-1] != s[ar[i][j]-1]:
#             cnt += 1
#             print("Y")
#     print(cnt)
# print(a[0][1],a[1][1],a[2][1])
# print(a[0][1]*a[1][1]*a[2][1]-cnt)
if n == 1 or n == 2 or n == 3:
    print(0)
    exit()
if len(a) != 3:
    print(0)
    exit()
for i in range(1,n//2+3):
    cnt = 0
    #print(i)
    for j in range(n):
        if cnt + 2*i > n-1:
            break
        x,y,z = s[cnt], s[cnt+i], s[cnt+2*i]
        #print(cnt, cnt+i, cnt+i+i)
        if x != y and y != z and z != x:
            ans += 1
        cnt += 1
print(a[0][1]*a[1][1]*a[2][1]-ans)

Buggy python submission (verdict: Runtime Error):
import collections
n = int(input())
s = list(input())
a = collections.Counter(s)
a = list(a.items())
ans = 0
ar = []
# for i in range(1,2000):
#     c_ar = []
#     for j in range(1,n+1,i):
#         c_ar.append(j)
#     if len(c_ar) >= 3:
#         ar.append(c_ar)
# print(ar)
# print(len(ar))
# for i in range(len(ar)):
#     print(ar[i])
#     print(len(ar[i]))
#     for j in range(len(ar[i])-2):
#         print(s[ar[i][j]-1],s[ar[i][j+1]-1],s[ar[i][j+2]-1])
#         print(ar[i][j]-1, ar[i][j+1]-1, ar[i][j+2]-1)
#         if s[ar[i][j]-1] != s[ar[i][j+1]-1] and s[ar[i][j+1]-1] != s[ar[i][j+2]-1] and s[ar[i][j+2]-1] != s[ar[i][j]-1]:
#             cnt += 1
#             print("Y")
#     print(cnt)
# print(a[0][1],a[1][1],a[2][1])
# print(a[0][1]*a[1][1]*a[2][1]-cnt)

for i in range(1,2000):
    cnt = 0
    for j in range(n):
        if cnt + 2*i > n-1:
            break
        x,y,z = s[cnt], s[cnt+i], s[cnt+2*i]
        if x != y and y != z and z != x:
            ans += 1
        cnt += 1
print(a[0][1]*a[1][1]*a[2][1]-ans)



Fixed submission:
import collections
n = int(input())
s = list(input())
a = collections.Counter(s)
a = list(a.items())
ans = 0
# ar = []
# for i in range(1,2000):
#     c_ar = []
#     for j in range(1,n+1,i):
#         c_ar.append(j)
#     if len(c_ar) >= 3:
#         ar.append(c_ar)
# print(ar)
# print(len(ar))
# for i in range(len(ar)):
#     print(ar[i])
#     print(len(ar[i]))
#     for j in range(len(ar[i])-2):
#         print(s[ar[i][j]-1],s[ar[i][j+1]-1],s[ar[i][j+2]-1])
#         print(ar[i][j]-1, ar[i][j+1]-1, ar[i][j+2]-1)
#         if s[ar[i][j]-1] != s[ar[i][j+1]-1] and s[ar[i][j+1]-1] != s[ar[i][j+2]-1] and s[ar[i][j+2]-1] != s[ar[i][j]-1]:
#             cnt += 1
#             print("Y")
#     print(cnt)
# print(a[0][1],a[1][1],a[2][1])
# print(a[0][1]*a[1][1]*a[2][1]-cnt)
if n == 1 or n == 2 or n == 3:
    print(0)
    exit()
if len(a) != 3:
    print(0)
    exit()
for i in range(1,n//2+3):
    cnt = 0
    #print(i)
    for j in range(n):
        if cnt + 2*i > n-1:
            break
        x,y,z = s[cnt], s[cnt+i], s[cnt+2*i]
        #print(cnt, cnt+i, cnt+i+i)
        if x != y and y != z and z != x:
            ans += 1
        cnt += 1
print(a[0][1]*a[1][1]*a[2][1]-ans)