def isValid(string: str) -> bool: return not (string.count('1')+string.count('0')) == (string.count('A')+string.count('B')+string.count('C') + 1) def convertStringToList(string) -> list: return [x for x in string] def evaluate(string): stringList = convertStringToList(string) if isValid(string): return -1 for x in range(0, len(stringList)-1, 2): if stringList[x+1] == 'A': stringList[x+2] = str(stringList[x] and stringList[x+2]) elif stringList[x+1] == 'B': stringList[x+2] = str(stringList[x] or stringList[x+2]) elif stringList[x+1] == 'C': stringList[x+2] = str(int(stringList[x]) ^ int(stringList[x+2])) return stringList[-1] string = input() print(evaluate(string))