function search(word) {
  //word=word.toLowerCase();
  var lower=0;
  var upper=wordList.length;
  var i=Math.floor(upper/2);
  while(i!=lower) {
    if(eval(wordList[i]==word)==true)
      return i;
    else if(eval(wordList[i]<word))
      lower=i;
    else
      upper=i;
    i=Math.floor((lower+upper)/2);
  }
  return -1;
}
function searchPrefix(word) {
  //word=word.toLowerCase();
  var len=word.length;
  var lower=0;
  var upper=wordList.length;
  var i=Math.floor(upper/2);
  while(i!=lower) {
    if(eval(wordList[i].substring(0,len)==word)==true)
      return i;
    else if(eval(wordList[i].substring(0,len)<word))
      lower=i;
    else
      upper=i;
    i=Math.floor((lower+upper)/2);
  }
  return -1;
}