js 10元买酒

10元买5瓶酒，2个盖子换一瓶，4个瓶子换一瓶，最多换多少个。
下面贴代码

function compute(yuan){    var num = yuan/2; var jiu = num; var gai = num ; var ping = num ;var total = num;    console.log(num,total)    recompute();    function recompute(){        if(ping>=4 || gai>=2){            total = total+parseInt(gai/2)+parseInt(ping/4);            jiu = parseInt(gai/2)+parseInt(ping/4);            gai = parseInt(gai%2) + jiu;            ping = parseInt(ping%4) + jiu;            console.log(total,jiu,gai,ping);            recompute();        }else{            return false        }       }    return total;}compute(10);