renamed files

diff --git a/answer_1.py b/challenge_1.py
similarity index 100%
rename from answer_1.py
rename to challenge_1.py

diff --git a/answer_2.py b/challenge_2.py
similarity index 100%
rename from answer_2.py
rename to challenge_2.py

diff --git a/answer_3.py b/challenge_3.py
similarity index 100%
rename from answer_3.py
rename to challenge_3.py

diff --git a/answer_4.py b/challenge_4.py
similarity index 100%
rename from answer_4.py
rename to challenge_4.py

diff --git a/answer_5.py b/challenge_5.py
similarity index 100%
rename from answer_5.py
rename to challenge_5.py

diff --git a/answer_6.py b/challenge_6.py
similarity index 100%
rename from answer_6.py
rename to challenge_6.py

diff --git a/answer_7.py b/challenge_7.py
similarity index 100%
rename from answer_7.py
rename to challenge_7.py

diff --git a/answer_8.py b/challenge_8.py
similarity index 100%
rename from answer_8.py
rename to challenge_8.py

diff --git a/answer_9.py b/challenge_9.py
similarity index 100%
rename from answer_9.py
rename to challenge_9.py