#include<iostream>
#include<string>
#include<algorithm>
using namespace std;
class palindrome
{
    public:
    void check(string input)
    {
        if(input.length()>100)
        {
            cout<<"Invalid input";
            return 0;
        }
        if(input.find('-')!=string::npos||(input[0]=='-'&&isdigit(input[1])))
        {
            cout<<"Invalid input";
            return;
        }
        string cleaned="";
        for(char ch:input)
        {
            if(isalnum(ch))
            {
                cleaned+=tolower(ch);
            }
        }
        if(cleaned.empty())
        {
            cout<<"Invalid input";
            return;
        }
        string rev=cleaned;
        reverse(rev.begin(),rev.end());
        if(cleaned==rev)
        cout<<"YES";
        else<<"NO";
    }
};
int main()
{
    string input;
    getline(cin,input);
    palindrome obj;
    obj.check(input);
    return 0;
}