import string
def checkio(text):
text = text.lower()
return max(string.ascii_lowercase, key=text.count)
if __name__ == '__main__':
print( checkio("Hellooaaaacccc bbbbWorld!") )
aW1wb3J0IHN0cmluZwogCmRlZiBjaGVja2lvKHRleHQpOgogICAgdGV4dCA9IHRleHQubG93ZXIoKQogICAgcmV0dXJuIG1heChzdHJpbmcuYXNjaWlfbG93ZXJjYXNlLCBrZXk9dGV4dC5jb3VudCkKICAgIAppZiBfX25hbWVfXyA9PSAnX19tYWluX18nOgoJcHJpbnQoIGNoZWNraW8oIkhlbGxvb2FhYWFjY2NjIGJiYmJXb3JsZCEiKSAp