a = str(input())
b = []
k = -1
g = 1
for i in range(len(a)):
    if a[i] == 'A':
        if a[i - 1] != 'A':
            k += 1
            b.append(g)
        else:
            b[k] += 1
res = ''
i = 0
f = 0
while i < len(b):
    if str(b[i]) not in res:
        res += str(b[i])
        f += 1
    else:
        s = str(b[i])
        while (i < len(b)) and (s in res):

            s += str(b[i])
            i += 1
        res += s
        if i < len(b):
            f += 1
    i += 1
print(f)