#include<iostream>
#include<string>
#include<cctype>
using namespace std;
int main(){
    string s;
    getline(cin,s);
    if(s.siz()>100||s.find('.')!=string::npos||(s[0]=='-'&&isdigit(s[1]))){
        cout << "INVALID INPUT";
        return 0;
    }
    bool num=true;
    for(char c:s)if(!
isdigit(c))num=false;
    if(num) t=s;
    else
       for(char c:s)
          if(isalnum(c))
t+=tolower(c);
    if(t.empty()){
        cout<<"INVALID INPUT";
        return 0;
    }
    string r=t;
reverse(r.begin(),r.end());
     cout<<(t==r ?"YES":"NO");
}