import sys
input = sys.stdin.readline

S=input().strip()

NOW=[0,0]

PX="c"
MX="a"
Y="b"
plus = 0

DICT={(0,0)}

for s in S:
    if s==PX:
        NOW[0]+=1
        
        PX, MX, Y = Y, PX, MX
        plus = 1 - plus

    elif s==MX:
        NOW[0]-=1
        
        PX, MX, Y = MX, Y, PX
        plus = 1 - plus

    else:
        if plus == 0:
            NOW[1]-=1
        else:
            NOW[1]+=1

        plus = 1 - plus

    DICT.add(tuple(NOW))

print(len(DICT))