Buggy python submission (verdict: Time Limit Exceeded):
S = input()
N = len(S)
i = 0
T = ""
while i <= N-2:
    if S[i] == 'B' and S[i+1] == 'C':
        T += 'D'
        i += 1
    else:
        T += S[i]
    i += 1


N = len(T)
ans = 0
l = 0
while l < N:

    if T[l] == 'B' or T[l] == 'C':
        l += 1
        continue
    
    r = l
    tmp = ''
    while r < N and (T[r] == 'A' or T[r] == 'D'):
        tmp += T[r]
        r += 1
    
    M = len(tmp)
    D_count = [0]*(M+1)
    for i in range(M-1, -1, -1):
        D_count[i] = D_count[i+1]
        if tmp[i] == 'D':
            D_count[i] += 1
    
    for i in range(M):
        if tmp[i] == 'A':
            ans += D_count[i]
    
    if r == N:
        break
    else:
        l = r+1

print(ans)





Fixed submission:
S = input()
N = len(S)
i = 0
T = []
while i <= N-2:
    if S[i] == 'B' and S[i+1] == 'C':
        T.append('D')
        i += 1
    else:
        T.append(S[i])
    i += 1

T = "".join(T)

N = len(T)
ans = 0
l = 0
while l < N:

    if T[l] == 'B' or T[l] == 'C':
        l += 1
        continue
    
    r = l
    tmp = []
    while r < N and (T[r] == 'A' or T[r] == 'D'):
        tmp.append(T[r])
        r += 1
    
    M = len(tmp)
    D_count = [0]*(M+1)
    for i in range(M-1, -1, -1):
        D_count[i] = D_count[i+1]
        if tmp[i] == 'D':
            D_count[i] += 1
    
    for i in range(M):
        if tmp[i] == 'A':
            ans += D_count[i]
    
    if r == N:
        break
    else:
        l = r+1

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
S = input()
N = len(S)
i = 0
T = ""
while i <= N-2:
    if S[i] == 'B' and S[i+1] == 'C':
        T += 'D'
        i += 1
    else:
        T += S[i]
    i += 1


N = len(T)
substring = []
l = 0
while l < N:

    if T[l] == 'B' or T[l] == 'C':
        l += 1
        continue
    
    r = l
    tmp = ''
    while r < N and (T[r] == 'A' or T[r] == 'D'):
        tmp += T[r]
        r += 1
    substring.append(tmp)
    if r == N:
        break
    else:
        l = r+1

ans = 0
for s in substring:
    M = len(s)
    D_count = [0]*(M+1)
    for i in range(M-1, -1, -1):
        D_count[i] = D_count[i+1]
        if s[i] == 'D':
            D_count[i] += 1
    
    for i in range(M):
        if tmp[i] == 'A':
            ans += D_count[i]

print(ans)





Fixed submission:
S = input()
N = len(S)
i = 0
T = []
while i <= N-2:
    if S[i] == 'B' and S[i+1] == 'C':
        T.append('D')
        i += 1
    else:
        T.append(S[i])
    i += 1

T = "".join(T)

N = len(T)
ans = 0
l = 0
while l < N:

    if T[l] == 'B' or T[l] == 'C':
        l += 1
        continue
    
    r = l
    tmp = []
    while r < N and (T[r] == 'A' or T[r] == 'D'):
        tmp.append(T[r])
        r += 1
    
    M = len(tmp)
    D_count = [0]*(M+1)
    for i in range(M-1, -1, -1):
        D_count[i] = D_count[i+1]
        if tmp[i] == 'D':
            D_count[i] += 1
    
    for i in range(M):
        if tmp[i] == 'A':
            ans += D_count[i]
    
    if r == N:
        break
    else:
        l = r+1

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
S = input()
N = len(S)
i = 0
T = ""
while i <= N-2:
    if S[i] == 'B' and S[i+1] == 'C':
        T += 'D'
        i += 1
    else:
        T += S[i]
    i += 1


N = len(T)
ans = 0
l = 0
while l < N:

    if T[l] == 'B' or T[l] == 'C':
        l += 1
        continue
    
    r = l
    tmp = ''
    while r < N and (T[r] == 'A' or T[r] == 'D'):
        tmp += T[r]
        r += 1
    
    M = len(tmp)
    D_count = [0]*(M+1)
    for i in range(M-1, -1, -1):
        D_count[i] = D_count[i+1]
        if tmp[i] == 'D':
            D_count[i] += 1
    
    for i in range(M):
        if T[i] == 'A':
            ans += D_count[i]
    
    if r == N:
        break
    else:
        l = r+1

print(ans)





Fixed submission:
S = input()
N = len(S)
i = 0
T = []
while i <= N-2:
    if S[i] == 'B' and S[i+1] == 'C':
        T.append('D')
        i += 1
    else:
        T.append(S[i])
    i += 1

T = "".join(T)

N = len(T)
ans = 0
l = 0
while l < N:

    if T[l] == 'B' or T[l] == 'C':
        l += 1
        continue
    
    r = l
    tmp = []
    while r < N and (T[r] == 'A' or T[r] == 'D'):
        tmp.append(T[r])
        r += 1
    
    M = len(tmp)
    D_count = [0]*(M+1)
    for i in range(M-1, -1, -1):
        D_count[i] = D_count[i+1]
        if tmp[i] == 'D':
            D_count[i] += 1
    
    for i in range(M):
        if tmp[i] == 'A':
            ans += D_count[i]
    
    if r == N:
        break
    else:
        l = r+1

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
S = input()
N = len(S)
i = 0
T = ""
while i <= N-2:
    if S[i] == 'B' and S[i+1] == 'C':
        T += 'D'
        i += 1
    else:
        T += S[i]
    i += 1


N = len(T)
substring = []
l = 0
while l < N:

    if T[l] == 'B' or T[l] == 'C':
        l += 1
        continue
    
    r = l
    tmp = ''
    while r < N and (T[r] == 'A' or T[r] == 'D'):
        tmp += T[r]
        r += 1
    substring.append(tmp)
    if r == N:
        break
    else:
        l = r+1

ans = 0
for s in substring:
    M = len(s)
    D_count = [0]*(M+1)
    for i in range(M-1, -1, -1):
        D_count[i] = D_count[i+1]
        if s[i] == 'D':
            D_count[i] += 1
    
    for i in range(M):
        if T[i] == 'A':
            ans += D_count[i]

print(ans)





Fixed submission:
S = input()
N = len(S)
i = 0
T = []
while i <= N-2:
    if S[i] == 'B' and S[i+1] == 'C':
        T.append('D')
        i += 1
    else:
        T.append(S[i])
    i += 1

T = "".join(T)

N = len(T)
ans = 0
l = 0
while l < N:

    if T[l] == 'B' or T[l] == 'C':
        l += 1
        continue
    
    r = l
    tmp = []
    while r < N and (T[r] == 'A' or T[r] == 'D'):
        tmp.append(T[r])
        r += 1
    
    M = len(tmp)
    D_count = [0]*(M+1)
    for i in range(M-1, -1, -1):
        D_count[i] = D_count[i+1]
        if tmp[i] == 'D':
            D_count[i] += 1
    
    for i in range(M):
        if tmp[i] == 'A':
            ans += D_count[i]
    
    if r == N:
        break
    else:
        l = r+1

print(ans)