import sys
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
def LS2(): return list(sys.stdin.readline().rstrip())


S = S()
N = len(S)
mod = 10**9+7

power = [1]  # power[i] = 2^i
for _ in range(N):
    power.append((power[-1]*2) % mod)

T = [(-1,1)]  # Sを縮約
prev = S[0]
count = 1
for s in S[1:]:
    if s == prev:
        count += 1
    else:
        T.append((ord(prev)-97,count))
        prev = s
        count = 1
T.append((ord(prev)-97,count))
M = len(T)-1

dp = [0]*(M+1)
# dp[i] = 左からi個目の文字で終わるような部分列に関する連の個数の和
S_dp = [0]*(M+1)
minus = [0]*26
s = 0
for i in range(1,M+1):
    char,count = T[i]
    x = (S_dp[i-1]+power[s]-minus[char])*(power[count]-1) % mod
    dp[i] = x
    S_dp[i] = (S_dp[i-1]+x) % mod
    minus[char] += power[s]*(power[count]-1)
    minus[char] %= mod
    s += count

ans = S_dp[-1]
print(ans)