l=[7,9,10,5,8,4,2,1,6,3,7,9,10,5,8,4,2]

y=["1","0","X","9","8","7","6","5","4","3","2"]

sum=0

if(len(s)>=18):

for i in range(0,len(s)-1):

sum+=int(s[i])*l[i]

if(sum!=0):

if y[sum%11].lower()==s[17].lower():

print("合法")

else:

print("不合法")

else:

print("不合法")