# include<stdio.h>
# include<string.h>
int main()
{
	char s1[100];
	int len,i,a=0,b;
    scanf("%s",&s1);
    len=strlen(s1);
    if(len%2==0)
    {
    	b=(len-1)%2; 
    	for(i=0;i<=b;i++)
		{
    		if(s1[i]==s1[len-1-i])
    		{
    			a++;
    		}
    
		
    	}
    	if(a==len/2)
    	{
    		printf("yes");
    	}
    	else
    	{
    		printf("no");	
    	}		
    }
    else
    {
    	b=(len-1)/2;
    	for(i=0;i<=b;i++)
		{
    		if(s1[i]==s1[len-1-i])
    		{
    			a++;
    		}
    
    	}
    	if(a==(len+1)/2)
    	{
    		printf("yes");
    	}
    	else
    	{
    		printf("no");	
    	}
    	
    }    		  
	return 0;
}