ss = input()

n = len(ss)
arrs = [ss[0]]

for i in range(1, n):
    if len(arrs[-1]) == 2:
        if arrs[-1].endswith(ss[i]):
            arrs.append('*')
        else:
            arrs.append(ss[i])

    else:
        if arrs[-1] == ss[i]:
            arrs.append(ss[i: i + 2])
        else:
            arrs.append(ss[i])

while '*' in arrs:
    arrs.remove('*')

print(len(arrs))