#!/usr/bin/env python

str = "ABBBCCDDZ"

parts = []
for i in range(len(str)):
  if len(parts)>0:
    if parts[len(parts)-1][len(parts[len(parts)-1])-1]==str[i]:
      parts[len(parts)-1] += str[i]
    else:
      parts.append(str[i])
  else:
    parts.append(str[i])

print parts