import sequtils
proc getchar_unlocked():char {. importc:"getchar_unlocked",header: "<stdio.h>" .}
proc getCWW(S:seq[int]):int =
  if S.len < 3: return 0
  var results = newSeq[int]()
  for a in 0..<S.len:
    for b in (a+1)..<S.len:
      for c in (b+1)..<S.len:
        if S[a] == 0  : continue
        if S[a] == S[b] : continue
        if S[b] != S[c] : continue
        let S2 = S[0..<a] & S[a+1..<b] & S[b+1..<c] & S[c+1..<S.len]
        results &= getCWW(S2) + (100 * S[a] + 10 * S[b] + S[c])
  if results.len == 0 : return 0
  return results.max()
var S = newSeq[int]()
while true:
  let k = getchar_unlocked()
  if k < '0': break
  S &= k.ord - '0'.ord
echo S.getCWW()