function _receiveFunds()
        internal
    {
        require(msg.value != 0);
        uint weiAmount = msg.value;
        uint transferTokens = weiAmount.mul(DECIMALS).div(currentPrice);

        _checkMaxSaleSupply(transferTokens);

        if(!investors[msg.sender]){
            countMembers = countMembers.add(1);
            investors[msg.sender] = true;
        }
        totalFunds = totalFunds.add(weiAmount);
        _mint(msg.sender, transferTokens);
    }