#思路,模拟

cmd1="reset"
cmd2=[["reset","board"],["board","add"],["board","delete"],["reboot","backplane"],["backplane","abort"]]
res=["board fault","where to add","no board at all","impossible","install first"] 



while True:
    try:
        a=input()
        if " " not in a:#一字串
            if a in cmd1 and a[0]=="r":
                print("reset what")
            else:
                print("unknown command")
        else:#两字串
            a=a.split()
            if len(a)>2:#超过2字串,直接未知命令
                print("unknown command")
            else:
                ans=""
                flag=0#是否唯一,默认唯一
                for i in cmd2:
                    if a[0]==i[0][:len(a[0])] and a[1]==i[1][:len(a[1])]:
                        flag+=1
                        ans=res[cmd2.index(i)]
                if flag==1:#唯一
                    print(ans)
                else:
                    print("unknown command")

    except:
        break