function init(address _tokens, address _users, address _flc) public {
        require(!_init);
        TOKENS_address = _tokens;
        USERS_address = _users;
        FLC_address = _flc;
        NRB_Tokens(TOKENS_address).init(address(this), _flc);
        NRB_Users(USERS_address).init(address(this), _flc);
        _init = true;
    }