#include<stdio.h>
main()
{char s[1000];
int c=0,a=0,i=0;
while(scanf("%s", s)!=EOF){
while(s[c]!=0){ c++;
}c--;
while(i<=c){
a+=s[i]==s[c]?0:1;
i++;
c--;
}
switch(a){
case 0:printf("yes\n"); break;
default :printf("no\n"); break;
}a=0;
while(a<=1000){s[a]=0;a++;}
c=a=i=0;
}
}