s=str(input())
ans=0
def f(s):
mx=0
for i in range(len(s),0,-1):
if '1'*i in s:
mx=i
break
return mx
if s.count('1')==0:
print(0)
elif s.count('1')==1:
print(1)
else:
lef,rig=0,0
for i in range(len(s)):
if s[i]=='1':
lef+=1
else:
break
for i in range(len(s)-1,-1,-1):
if s[i]=='1':
rig+=1
else:
break
res=f(s)
print(max(res,min(lef+rig,len(s))))