Buggy python submission (verdict: Runtime Error):
s=input()
n=len(s)
a=0
i=0
p=s[0]
while i<n-1:
  if s[i+1]==p:
    i+=2
  else:
    if i==n-2:a+=1
    i+=1
  a+=1
  p=s[i]
print(a)

Fixed submission:
from heapq import heappush,heappop,heapify
from collections import deque,defaultdict,Counter
import itertools
from itertools import permutations,combinations,groupby
import sys
import bisect
import string
import math
import time
import random
def S_():
    return input()
def LS():
    return [i for i in input().split()]
def I():
    return int(input())
def MI():
    return map(int,input().split())
def LI():
    return [int(i) for i in input().split()]
def LI_():
    return [int(i)-1 for i in input().split()]
def StoI():
    return [ord(i)-97 for i in input()]
def ItoS(nn):
    return chr(nn+97)
def GI(V,E,Directed=False,index=0):
    org_inp=[]
    g=[[] for i in range(n)]
    for i in range(E):
        inp=LI()
        org_inp.append(inp)
        if index==0:
            inp[0]-=1
            inp[1]-=1
        if len(inp)==2:
            a,b=inp
            g[a].append(b)
            if not Directed:
                g[b].append(a)
        elif len(inp)==3:
            a,b,c=inp
            aa=(inp[0],inp[2])
            bb=(inp[1],inp[2])
            g[a].append(bb)
            if not Directed:
                g[b].append(aa)
    return g,org_inp
def bit_combination(k,n=2):
    rt=[]
    for tb in range(n**k):
        s=[tb//(n**bt)%n for bt in range(k)]
        rt+=[s]
    return rt
def show(*inp,end='\n'):
    if show_flg:
        print(*inp,end=end)
YN=['Yes','No']
mo=10**9+7
inf=float('inf')
l_alp=string.ascii_lowercase
u_alp=string.ascii_uppercase
ts=time.time()
#sys.setrecursionlimit(10**5)
input=lambda: sys.stdin.readline().rstrip()

def ran_input():
    import random
    n=random.randint(4,16)
    rmin,rmax=1,10
    a=[random.randint(rmin,rmax) for _ in range(n)]
    return n,a

show_flg=False
show_flg=True

ans=1

s=StoI()
n=len(s)
dp=[[0]*n for i in range(2)]

for i in range(n):
    if i==0:
        dp[0][i]=1
    elif i==1:
        if s[1]==s[0]:
            dp[0][i]=0
            dp[1][i]=1
        else:
            dp[0][i]=2
            dp[1][i]=1
    else:
        if s[i]==s[i-1]:
            dp[0][i]=dp[1][i-1]+1
            dp[1][i]=max(dp[0][i-2],dp[1][i-2])+1
        else:
            dp[0][i]=max(dp[0][i-1],dp[1][i-1])+1
            dp[1][i]=max(dp[0][i-2],dp[1][i-2])+1

ans=max(dp[0][n-1],dp[1][n-1])
print(ans)

Buggy python submission (verdict: Runtime Error):
s=input()
n=len(s)
a=0
p=''
while i<n:
  if s[i]==p:
    i+=2
  else:
    i+=1
  a+=1
print(a)

Fixed submission:
from heapq import heappush,heappop,heapify
from collections import deque,defaultdict,Counter
import itertools
from itertools import permutations,combinations,groupby
import sys
import bisect
import string
import math
import time
import random
def S_():
    return input()
def LS():
    return [i for i in input().split()]
def I():
    return int(input())
def MI():
    return map(int,input().split())
def LI():
    return [int(i) for i in input().split()]
def LI_():
    return [int(i)-1 for i in input().split()]
def StoI():
    return [ord(i)-97 for i in input()]
def ItoS(nn):
    return chr(nn+97)
def GI(V,E,Directed=False,index=0):
    org_inp=[]
    g=[[] for i in range(n)]
    for i in range(E):
        inp=LI()
        org_inp.append(inp)
        if index==0:
            inp[0]-=1
            inp[1]-=1
        if len(inp)==2:
            a,b=inp
            g[a].append(b)
            if not Directed:
                g[b].append(a)
        elif len(inp)==3:
            a,b,c=inp
            aa=(inp[0],inp[2])
            bb=(inp[1],inp[2])
            g[a].append(bb)
            if not Directed:
                g[b].append(aa)
    return g,org_inp
def bit_combination(k,n=2):
    rt=[]
    for tb in range(n**k):
        s=[tb//(n**bt)%n for bt in range(k)]
        rt+=[s]
    return rt
def show(*inp,end='\n'):
    if show_flg:
        print(*inp,end=end)
YN=['Yes','No']
mo=10**9+7
inf=float('inf')
l_alp=string.ascii_lowercase
u_alp=string.ascii_uppercase
ts=time.time()
#sys.setrecursionlimit(10**5)
input=lambda: sys.stdin.readline().rstrip()

def ran_input():
    import random
    n=random.randint(4,16)
    rmin,rmax=1,10
    a=[random.randint(rmin,rmax) for _ in range(n)]
    return n,a

show_flg=False
show_flg=True

ans=1

s=StoI()
n=len(s)
dp=[[0]*n for i in range(2)]

for i in range(n):
    if i==0:
        dp[0][i]=1
    elif i==1:
        if s[1]==s[0]:
            dp[0][i]=0
            dp[1][i]=1
        else:
            dp[0][i]=2
            dp[1][i]=1
    else:
        if s[i]==s[i-1]:
            dp[0][i]=dp[1][i-1]+1
            dp[1][i]=max(dp[0][i-2],dp[1][i-2])+1
        else:
            dp[0][i]=max(dp[0][i-1],dp[1][i-1])+1
            dp[1][i]=max(dp[0][i-2],dp[1][i-2])+1

ans=max(dp[0][n-1],dp[1][n-1])
print(ans)

Buggy python submission (verdict: Runtime Error):
s=input()
a=0
p=''
while i<n:
  if s[i]==p:
    i+=2
  else:
    i+=1
  a+=1
print(a)

Fixed submission:
from heapq import heappush,heappop,heapify
from collections import deque,defaultdict,Counter
import itertools
from itertools import permutations,combinations,groupby
import sys
import bisect
import string
import math
import time
import random
def S_():
    return input()
def LS():
    return [i for i in input().split()]
def I():
    return int(input())
def MI():
    return map(int,input().split())
def LI():
    return [int(i) for i in input().split()]
def LI_():
    return [int(i)-1 for i in input().split()]
def StoI():
    return [ord(i)-97 for i in input()]
def ItoS(nn):
    return chr(nn+97)
def GI(V,E,Directed=False,index=0):
    org_inp=[]
    g=[[] for i in range(n)]
    for i in range(E):
        inp=LI()
        org_inp.append(inp)
        if index==0:
            inp[0]-=1
            inp[1]-=1
        if len(inp)==2:
            a,b=inp
            g[a].append(b)
            if not Directed:
                g[b].append(a)
        elif len(inp)==3:
            a,b,c=inp
            aa=(inp[0],inp[2])
            bb=(inp[1],inp[2])
            g[a].append(bb)
            if not Directed:
                g[b].append(aa)
    return g,org_inp
def bit_combination(k,n=2):
    rt=[]
    for tb in range(n**k):
        s=[tb//(n**bt)%n for bt in range(k)]
        rt+=[s]
    return rt
def show(*inp,end='\n'):
    if show_flg:
        print(*inp,end=end)
YN=['Yes','No']
mo=10**9+7
inf=float('inf')
l_alp=string.ascii_lowercase
u_alp=string.ascii_uppercase
ts=time.time()
#sys.setrecursionlimit(10**5)
input=lambda: sys.stdin.readline().rstrip()

def ran_input():
    import random
    n=random.randint(4,16)
    rmin,rmax=1,10
    a=[random.randint(rmin,rmax) for _ in range(n)]
    return n,a

show_flg=False
show_flg=True

ans=1

s=StoI()
n=len(s)
dp=[[0]*n for i in range(2)]

for i in range(n):
    if i==0:
        dp[0][i]=1
    elif i==1:
        if s[1]==s[0]:
            dp[0][i]=0
            dp[1][i]=1
        else:
            dp[0][i]=2
            dp[1][i]=1
    else:
        if s[i]==s[i-1]:
            dp[0][i]=dp[1][i-1]+1
            dp[1][i]=max(dp[0][i-2],dp[1][i-2])+1
        else:
            dp[0][i]=max(dp[0][i-1],dp[1][i-1])+1
            dp[1][i]=max(dp[0][i-2],dp[1][i-2])+1

ans=max(dp[0][n-1],dp[1][n-1])
print(ans)