MOD = 10 ** 9 + 7
S = input()
dp = [0] * 27
dp2 = [0] * 27
dp[0] = 1
for s in S:
    i = ord(s) - 96
    dp2[i] += sum(dp2)
    dp2[i] += sum(dp) - dp[i]
    dp[i] += sum(dp)
    dp[i] %= MOD
    dp2[i] %= MOD
print(sum(dp2) % MOD)