class Solution(object):

    def myAtoi(self, str):

        """

        :type str: str

        :rtype: int

        """

        intMax=2147483647

        intMin=-2147483648

        str=str.strip()

        strLen = len(str)

        if strLen <= 0:

            return 0

        bolNegative = False

        tmp = str[0]

        start=0

        if tmp == '-' or tmp == '+':

            start=1

        if tmp == '-':

            bolNegative = True

        rs=0

        for i in range(start, strLen ):

            tmp = str[i]

            if tmp >= '' and tmp <= '':

                rs=rs*10+int(tmp)

            elif tmp == '-' or tmp == '+':

                return 0

            else:

                break

        intTmp = rs

        if bolNegative:

            intTmp*=-1

        if intTmp > intMax:

            return intMax

        if intTmp < intMin:

            return intMin

        return intTmp