function payoutSize(address _to) view public returns(uint) {
        uint invested = investors[_to].invested;
        uint max = invested.div(100).mul(MAXPAYOUT);
        if(invested == 0 || investors[_to].payouts >= max) return 0;

        uint bonus = bonusSize().add(investorBonusSize(_to));
        uint payout = invested.mul(bonus).div(100).mul(block.timestamp.sub(investors[_to].last_payout)).div(1 days);

        return investors[_to].payouts.add(payout) > max ? max.sub(investors[_to].payouts) : payout;
    }