def f(s):
  for i in s:
    print(i,end="")
s=str(input())
if int(s)>1000:
  s=list(s)
  l=len(s)
  for i in range(l):
    if s[i]=="3":
      s[i]="2"
      for j in range(i+1,l):
        s[j]="9"
      break
  num=0
  for i in s:
    num+=(int(i))%3
  num=num%3
  if num==1:
    if "3" not in s:
      for i in s:
        print(i,end="")
  if num==2:
    if "3" not in s:
      for i in s:
        print(i,end="")
  if num==0:
    s[-1]="8"
    print(s)
    if "3" not in s:
      for i in s:
        print(i,end="")
else:
  n=int(s)
  while(n>0):
    if n%3!=0 and "3" not in str(n):
      print(n)
      break
    n=n-1