import re


s1="a3[b2[c1[d]]]e"
def decode(string1):
   m = re.match("([^0-9]*)(\d)\[(.*)\]([^0-9]*)", string1)
   if m:
      return m.groups()[0] + decode(m.groups()[2]) * int(m.groups()[1]) + m.groups()[3]
   else:
      return string1
print decode(s1)