#include <iostream>
#include <string>
using namespace std;
 
int main(void){
    while(1){
        int flag = 0;
        string str;
        getline(cin, str);
 
        if(str == "0")
            return 0;
 
        for(int i = 0; i < str.length() / 2; i++){
            if(str[i] != str[str.length() - i - 1]){
                flag = 1;
                cout << "no\n";
                break;
            }
        }
 
        if(flag == 0)
            cout << "yes\n";
    }
}

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OQo5NwoxMzkzMQow

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