en2asc = lambda s: ord(s) - 97

S = input()
MOD = 10 ** 9 + 7
ct = [0] * 26
ct_sum = 0
run = [0] * 26
run_sum = 0
p2 = 1

for s in S:
    i = en2asc(s)
    ct[i] += p2
    ct[i] %= MOD
    ct_sum += p2
    ct_sum %= MOD
    p2 *= 2
    p2 %= MOD

    r0 = run[i]
    run[i] *= 2
    run[i] += 1

    run[i] += run_sum + ct_sum - r0 - ct[i]
    run_sum += run[i] - r0
    run[i] %= MOD
    run_sum %= MOD
print(run_sum)