a = [ord(i)-ord("a") for i in input()]
mod = 10**9+7
n = len(a)
count = [0]*26
two = [1]
for i in range(n):
    two.append(two[-1]*2%mod)
ans = 0
for i in range(n):
    ans += ((two[i]-count[a[i]])*two[n-1-i])%mod
    ans %= mod
    count[a[i]] += two[i]
    count[a[i]] %= mod
print(ans)