safem = {
  map: null,
  
  convert: function(a) {
    safem.init();
    
    var s = "";
    for (i=0; i < a.length; i++) {
      var b = a.charAt(i);
      s += ((b>='A' && b<='Z') || (b>='a' && b<='z') ? safem.map[b] : b);
    }
    return s;
  },
    
  init: function() {
    if (safem.map != null)
    return;
    
    var map = new Array();
    var s = "abcdefghijklmnopqrstuvwxyz";
    
    for (i=0; i<s.length; i++)
    map[s.charAt(i)] = s.charAt((i+13)%26);
    for (i=0; i<s.length; i++)
    map[s.charAt(i).toUpperCase()] = s.charAt((i+13)%26).toUpperCase();
    
    safem.map = map;
  },
    
  write: function(a) {
    document.write(safem.convert(a));
  }
}