#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