MOD = 10**9+7
HALF = pow(2, MOD-2, MOD)
s = input()
n = len(s)
pos = [[] for _ in range(26)]
for i in range(n):
	pos[ord(s[i])-97].append(i)

ans = pow(2, n, MOD) - 1
for i in range(1, n):
	ans += (n-i) * pow(2, n-1-i, MOD)
	ans %= MOD

for p in pos:
	l = len(p)
	cur = 0
	for i in range(l-1):
		d = p[i+1] - p[i]
		cur *= pow(HALF, d, MOD)
		cur += pow(2, n-1-d, MOD)
		cur %= MOD
		ans -= cur
		ans %= MOD

print(ans)