环形删除数字

while True:
    try:
        n=int(input())
        if n >1000:
            n=1000
        zeros=n*[0]
        index=0
        count=0
        flag=n
        while flag>1:
            if zeros[index]==0:
                count=count+1
                if count==3:
                    zeros[index]=1
                    count=0
                    flag=flag-1
            index=(index+1)%n
        print(zeros.index(0))
    except:
        break