try:
while(True):
judge = 1 #用來做是否為迴文的判斷(judge == 1代表是迴文,judge == 0代表不是迴文)
str = input()
for i in range(len(str)//2): #只需跑前半段長度的迴圈
if(str[i] == str[len(str)-1-i]): #第一項與最後一項比,以此類推
judge = 1
else: #如果出現了前後字符不相等的情況,則judge = 0
judge = 0
break
if(judge == 1): #最後再來判斷
print("yes")
else:
print("no")
except EOFError:
pass