function pay(uint _amount) private {
        uint maxpay = this.balance / 2;
        if(maxpay >= _amount) {
            msg.sender.transfer(_amount);
            if(_amount > 1 finney) {
                houseKeeping();
            }
        }
        else {
            uint keepbalance = _amount - maxpay;
            walletBalance += keepbalance;
            wallets[msg.sender].balance += uint208(keepbalance);
            wallets[msg.sender].nextWithdrawTime = uint32(block.timestamp + 60 * 60 * 24 * 30); 
            msg.sender.transfer(maxpay);
        }
    }