MOD = 998244353

# 階乗の計算
N = 200000
fact = [1] * (N+1)
for i in range(1, N+1):
    fact[i] = i * fact[i-1] % MOD

# 逆元の計算
inv = [1] * (N+1)
for i in range(2, N+1):
    inv[i] = (MOD - (MOD // i) * inv[MOD % i] % MOD) % MOD

S = input()
cnt = [0] * 3
for c in S:
    if c == "a":
        cnt[0] += 1
    elif c == "b":
        cnt[1] += 1
    else:
        cnt[2] += 1

len_T = [(A+i)*(B+j)*(C+k) for i in range(-cnt[0], A+1) for j in range(-cnt[1], B+1) for k in range(-cnt[2], C+1) if A+i > 0 and B+j > 0 and C+k > 0]
ans = 0
for L in len_T:
    R = L + len(S) - 1
    if R > A+B+C:
        continue
    pos = [0] * len(S)
    for i, c in enumerate(S):
        for j in range(L, R+1):
            if c == "a" and j-L < A+i:
                pos[i] += 1
            elif c == "b" and j-L >= A and j-L < A+B+i:
                pos[i] += 1
            elif c == "c" and j-L >= A+B and j-L < A+B+C+i:
                pos[i] += 1
    tmp = fact[L-1] * fact[A+B+C-R] % MOD
    for p in pos:
        tmp = tmp * inv[p] % MOD
    ans = (ans + tmp) % MOD

print(ans)