import sys
def f(s):
  for i in s:
    print(i,end="")
s=str(input())
s=list(s)
if len(s)>4:
 while True:
  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:
      for i in s:
        print(i,end="")
      sys.exit()
  if num==2:
      for i in s:
        print(i,end="")
      sys.exit()
  if num==0:
    for i in range(1,l):
      if 1<=int(s[-i]):
        s[-i]=str(int(s[-i])-1)
        break
      else:
        s[-i]="9"
    if "3" not in s:
      for i in s:
        print(i,end="")
      sys.exit()
      break
else:
  n=int(str(s))
  while(n>0):
    if n%3!=0 and "3" not in str(n):
      print(n)
    n=n-1