#include<iostream>
#include<string>
#include<algorithm>
#include<cctype>
using namespace std;
bool ipal(string s){
    string org = 's';
    rev(s.begin(),s.end());
    return org ==s;
    
}
int main(){
    string ip;
    getline(cin,ip);
    if(ip,length()>100){
        cout<<"Invalid input";
        return 0;
    }
    if (ip[0] =='-' || ip.find('.') != string::npos){
         cout<<"Invalid input";
         return 0;
    }
    string c = "";
    for (char ch : ip){
        if(isalnum(ch)){
            c += tolower(ch);
        }
    }
    if(c.empty()){
         cout<<"Invalid input";
         return 0;
    }
        if(ipal(c)){
            cout<<"YES";
            
        }else{
            cout<<"NO";
        }
    return 0;
}