import os
from string import zfill
def  command(str) :
      x = os.system(str)
      if x != 0 : raise Exception

def readlines(filename) :
  f1=open(filename)
  lines=f1.readlines()
  f1.close()
  return lines

def NZname(N,Z,str) :
  Zs=zfill(Z,3)
  Ns=zfill(N,3)
  NZs=Ns+'.'+Zs
  return NZs+str
  
def path_to(N,Z) :
# with trailing '/'
  Zs=zfill(Z,3)
  Ns=zfill(N,3)
  NZs=Ns+'.'+Zs
  return Zs+'/'+NZs+'/'