Buggy python submission (verdict: Runtime Error):
n=int(input())
if n<3:
    print(0)
    exit()
if n==3:
    print(1)
    exit()
s=input()
s=[int(i)+1 for i in s]
l=[int(i) for i in s]
l1=[0]*(n+16) 
l2=[0]*(n+13)
l3=[0]*(n+12)
l2[n-1]=1 
l3[s[n-1]-1]=1 
k=3 
for i in range(n-2,-1,-1): 
    l2[i]=l2[i+1]
    if l3[s[i]-1]==0:
        l2[i]+=1 
        l3[s[i]-1]=1 
for j in range(1,k):
    l3=[0]*n 
    l1[n-1]=0 
    for i in range(n-2,-1,-1) : 
        l1[i]=l1[i+1]
        l1[i]=l1[i]+l2[i+1]
        l1[i]=l1[i]-l3[s[i]-1]
        l3[s[i]-1]=l2[i+1]
    l2=l1[:]
print(l1[0])

Fixed submission:
n=int(input())
if n<3:
    print(0)
    exit()
if n==3:
    print(1)
    exit()
s=input()
s=[int(i)+1 for i in s]
l=[int(i) for i in s]
l1=[0]*(n+16) 
l2=[0]*(n+13)
l3=[0]*(n+12)
l2[n-1]=1 
l3[s[n-1]-1]=1 
k=3 
for i in range(n-2,-1,-1): 
    l2[i]=l2[i+1]
    if l3[s[i]-1]==0:
        l2[i]+=1 
        l3[s[i]-1]=1 
for j in range(1,k):
    l3=[0]*(n+18)
    l1[n-1]=0 
    for i in range(n-2,-1,-1) : 
        l1[i]=l1[i+1]
        l1[i]=l1[i]+l2[i+1]
        l1[i]=l1[i]-l3[s[i]-1]
        l3[s[i]-1]=l2[i+1]
    l2=l1[:]
print(l1[0])

Buggy python submission (verdict: Runtime Error):
n=int(input())
s=input()
s=[int(i)+1 for i in s]
l=[int(i) for i in s]
l1=[0]*(n+62332) 
l2=[0]*(n+32323)
l3=[0]*(n+23333)
l2[n-1]=1 
l3[s[n-1]-1]=1 
k=3 
for i in range(n-2,-1,-1): 
    l2[i]=l2[i+1]
    if l3[s[i]-1]==0:
        l2[i]+=1 
        l3[s[i]-1]=1 
for j in range(1,k):
    l3=[0]*n 
    l1[n-1]=0 
    for i in range(n-2,-1,-1) : 
        l1[i]=l1[i+1]
        l1[i]=l1[i]+l2[i+1]
        l1[i]=l1[i]-l3[s[i]-1]
        l3[s[i]-1]=l2[i+1]
    l2=l1[:]
print(l1[0])

Fixed submission:
n=int(input())
if n<3:
    print(0)
    exit()
if n==3:
    print(1)
    exit()
s=input()
s=[int(i)+1 for i in s]
l=[int(i) for i in s]
l1=[0]*(n+16) 
l2=[0]*(n+13)
l3=[0]*(n+12)
l2[n-1]=1 
l3[s[n-1]-1]=1 
k=3 
for i in range(n-2,-1,-1): 
    l2[i]=l2[i+1]
    if l3[s[i]-1]==0:
        l2[i]+=1 
        l3[s[i]-1]=1 
for j in range(1,k):
    l3=[0]*(n+18)
    l1[n-1]=0 
    for i in range(n-2,-1,-1) : 
        l1[i]=l1[i+1]
        l1[i]=l1[i]+l2[i+1]
        l1[i]=l1[i]-l3[s[i]-1]
        l3[s[i]-1]=l2[i+1]
    l2=l1[:]
print(l1[0])

Buggy python submission (verdict: Runtime Error):
n=int(input())
s=input()
s=[int(i)+1 for i in s]
l=[int(i) for i in s]
l1=[0]*(n+293) 
l2=[0]*(n+323)
l3=[0]*(n+233)
l2[n-1]=1 
l3[s[n-1]-1]=1 
k=3 
for i in range(n-2,-1,-1): 
    l2[i]=l2[i+1]
    if l3[s[i]-1]==0:
        l2[i]+=1 
        l3[s[i]-1]=1 
for j in range(1,k):
    l3=[0]*n 
    l1[n-1]=0 
    for i in range(n-2,-1,-1) : 
        l1[i]=l1[i+1]
        l1[i]=l1[i]+l2[i+1]
        l1[i]=l1[i]-l3[s[i]-1]
        l3[s[i]-1]=l2[i+1]
    l2=l1[:]
print(l1[0])

Fixed submission:
n=int(input())
if n<3:
    print(0)
    exit()
if n==3:
    print(1)
    exit()
s=input()
s=[int(i)+1 for i in s]
l=[int(i) for i in s]
l1=[0]*(n+16) 
l2=[0]*(n+13)
l3=[0]*(n+12)
l2[n-1]=1 
l3[s[n-1]-1]=1 
k=3 
for i in range(n-2,-1,-1): 
    l2[i]=l2[i+1]
    if l3[s[i]-1]==0:
        l2[i]+=1 
        l3[s[i]-1]=1 
for j in range(1,k):
    l3=[0]*(n+18)
    l1[n-1]=0 
    for i in range(n-2,-1,-1) : 
        l1[i]=l1[i+1]
        l1[i]=l1[i]+l2[i+1]
        l1[i]=l1[i]-l3[s[i]-1]
        l3[s[i]-1]=l2[i+1]
    l2=l1[:]
print(l1[0])