def compress(data):
    data=toBinary(data)

    Dict = {}
    Dict['0'] = 0
    Dict['1'] = 1

    N=2
    i=0

    result=elias_generic(len(data))
    while i<len(data):

          maxPref=1
          while i+maxPref+1<=len(data):
                cur_str=data[i:i+maxPref+1]
                if Dict.get(cur_str)==None:
                    break
                maxPref+=1

          # increase length if we are at the end
          s=''
          while Dict.get(data[i:i + maxPref]+s)==-1:
                s+='0'
          cur_str = data[i:i + maxPref]+s

          # find index of element in lexicon and remove old word
          ind=Dict.get(cur_str)
          Dict[cur_str]=-1

          # add new lexicon words
          Dict[cur_str+'0']=ind
          Dict[cur_str+'1']=N+1

          N+=1
          i+=len(cur_str)

          compressed_len=int(math.log(N-1, 2))+1
          bin_ind="{0:b}".format(ind)
          result+= '0'*(compressed_len-len(bin_ind))+bin_ind

    return result