Buggy python submission (verdict: Time Limit Exceeded):
from collections import Counter
n=int(input())
s=list(input())
C=Counter(s)
r,g,b=C["R"],C["G"],C["B"]
ans=r*g*b

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

print(ans)

Fixed submission:
from collections import Counter
n=int(input())
s=list(input())
C=Counter(s)
r,g,b=C["R"],C["G"],C["B"]
ans=r*g*b

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

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
n=int(input())
s=input()
r=s.count("R")
g=s.count("G")
b=s.count("B")
ans=r*g*b

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

print(ans)

Fixed submission:
from collections import Counter
n=int(input())
s=list(input())
C=Counter(s)
r,g,b=C["R"],C["G"],C["B"]
ans=r*g*b

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

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
n=int(input())
s=input()
r=s.count("R")
g=s.count("G")
b=s.count("B")
ans=r*g*b

for i in range(n-2):
    for j in range(i+1,n-1):
        if 2*j-i<=n-1:
            a,b,c=s[i],s[j],s[2*j-i]
            if a==b or b==c or c==a:
                pass
            else:
                ans-=1

print(ans)

Fixed submission:
from collections import Counter
n=int(input())
s=list(input())
C=Counter(s)
r,g,b=C["R"],C["G"],C["B"]
ans=r*g*b

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

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
n=int(input())
s=input()
R=[]
G=[]
B=[]

for i in range(n):
    if s[i]=="R":
        R.append(i)
    elif s[i]=="G":
        G.append(i)
    else:
        B.append(i)

b=len(B)
ans=0

for j in R:
    for k in G:
        cnt=b
        if 2*j-k in B:cnt-=1
        if 2*k-j in B:cnt-=1
        if (j+k)/2 in B:cnt-=1
        ans+=cnt

print(ans)


Fixed submission:
from collections import Counter
n=int(input())
s=list(input())
C=Counter(s)
r,g,b=C["R"],C["G"],C["B"]
ans=r*g*b

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

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
n=int(input())
s=input()
R=[]
G=[]
B=[]

for i in range(n):
    if s[i]=="R":
        R.append(i)
    elif s[i]=="G":
        G.append(i)
    else:
        B.append(i)

b=len(B)
ans=0

for j in R:
    for k in G:
        cnt=b
        if 2*j-k in B:cnt-=1
        if 2*k-j in B:cnt-=1
        if (j+k)/2 in B:cnt-=1
        ans+=cnt

print(ans)

Fixed submission:
from collections import Counter
n=int(input())
s=list(input())
C=Counter(s)
r,g,b=C["R"],C["G"],C["B"]
ans=r*g*b

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

print(ans)