import sys
input = sys.stdin.readline

S = input()[:-1]
N = len(S)
sub = [0]*26
ans = 0
MOD = 10**9+7

for i in range(N):
    j = ord(S[i])-ord('a')
    ans += (pow(2, i, MOD)-sub[j])*pow(2, N-1-i, MOD)
    ans %= MOD
    sub[j] += pow(2, i, MOD)
    sub[j] %= MOD

print(ans)