Return True if the concrete value of the input_string ends with suffix
    otherwise false.

    :param input_string: the string we want to transform in an integer
    :param bitlength: bitlength of the bitvector representing the index of the substring

    :return BVV: bit-vector representation of the integer resulting from ythe string or -1 in bitvector representation
                 if the string cannot be transformed into an integer

def StrToInt(input_string, bitlength):
    """
    Return True if the concrete value of the input_string ends with suffix
    otherwise false.

    :param input_string: the string we want to transform in an integer
    :param bitlength: bitlength of the bitvector representing the index of the substring

    :return BVV: bit-vector representation of the integer resulting from ythe string or -1 in bitvector representation
                 if the string cannot be transformed into an integer
    """
    try:
        return BVV(int(input_string.value), bitlength)
    except ValueError:
        return BVV(-1, bitlength)