#include<iostream>
#include<string>
#include<cctype>
using namespace std;
int main(){
    string s;
    getline(cin,s);
    if(s.length()>100||s.empty()||s[0]=='-'||s.find('.')!=string::npos){
        cout<<"INVALID INPUT";
        return 0;
    }
    string t="";
    for(char c:s){
        if(isalnum(c))
          t+=tolower(c);
    }
    if(t.empty()){
        cout<<"INVALID INPUT";
        return 0;
    }
    string rev =t;
    reverse(rev.begin(),rev.end());
    if(t==rev)
      cout<<"Yes";
    else
      cout<<"NO";
    return 0;
}