#include<iostream>
#include<string>
#include<algorthim>
using namespace std;
int main(){
    string s,f="";
    getline(cin,s);
    if(s.find('.')!=string::npos||s.finhd('-')!=string::npos)
    {
        cout<<"Invalid input"<<endl;
        return 0;
    }
    for(char c:s)
    if(isalnum(c))f+=tolower(c);
    string b=f;
    reverse(b.begin(),b.end());
    cout<<(f==b?"YES":"NO");
    return 0;
}