text: #include <bits/stdc++.h>
  
  int main()
  {
      std::ios::sync_with_stdio(false);
  
      std::string line;
      while (std::getline(std::cin, line))
      {
          if (line == "0")
              break;
  
          std::cout << ((line == std::string(rbegin(line), rend(line))) ? "yes" : "no") << '\n';
      }
  }
  