a = [ord(i)-ord("a") for i in input()]
mod = 10**9+7
n = len(a)
count = [0]*26

ans = 0
for i in range(n):
    x = pow(2,i,mod)
    ans += ((x-count[a[i]])*pow(2,n-1-i,mod))%mod
    ans %= mod
    count[a[i]] += x
    count[a[i]] %= mod
print(ans)