MOD = 10**9 + 7

S = input().strip()
N = len(S)

# Precompute powers of 2 modulo MOD up to N
pow2 = [1] * (N + 2)
for i in range(1, N + 2):
    pow2[i] = (pow2[i-1] * 2) % MOD

from collections import defaultdict

char_positions = defaultdict(list)
for idx, c in enumerate(S):
    char_positions[c].append(idx)

sum_sub = 0

for c in char_positions:
    positions = char_positions[c]
    sum_c = 0
    for j in range(len(positions)):
        pos = positions[j]
        if j == 0:
            sum_c = pow2[pos]
            continue
        exponent = N - pos - 1
        if exponent < 0:
            term = 0
        else:
            term = (sum_c * pow2[exponent]) % MOD
        sum_sub = (sum_sub + term) % MOD
        sum_c = (sum_c + pow2[pos]) % MOD

# Compute N * pow2[N-1] mod MOD
pow_N_1 = pow2[N-1]
total = (pow_N_1 * N) % MOD
ans = (total - sum_sub) % MOD

print(ans)