diff --git a/.pytest_cache/README.md b/.pytest_cache/README.md
new file mode 100644
index 0000000..bb78ba0
--- /dev/null
+++ b/.pytest_cache/README.md
@@ -0,0 +1,8 @@
+# pytest cache directory #
+
+This directory contains data from the pytest's cache plugin,
+which provides the `--lf` and `--ff` options, as well as the `cache` fixture.
+
+**Do not** commit this to version control.
+
+See [the docs](https://docs.pytest.org/en/latest/cache.html) for more information.
diff --git a/.pytest_cache/v/cache/lastfailed b/.pytest_cache/v/cache/lastfailed
new file mode 100644
index 0000000..9e26dfe
--- /dev/null
+++ b/.pytest_cache/v/cache/lastfailed
@@ -0,0 +1 @@
+{}
\ No newline at end of file
diff --git a/.pytest_cache/v/cache/nodeids b/.pytest_cache/v/cache/nodeids
new file mode 100644
index 0000000..ac8b7cd
--- /dev/null
+++ b/.pytest_cache/v/cache/nodeids
@@ -0,0 +1,3 @@
+[
+  "factorial.py::test_factorial"
+]
\ No newline at end of file
diff --git a/__pycache__/factorial.cpython-36-PYTEST.pyc b/__pycache__/factorial.cpython-36-PYTEST.pyc
new file mode 100644
index 0000000..a65b553
Binary files /dev/null and b/__pycache__/factorial.cpython-36-PYTEST.pyc differ
diff --git a/factorial.py b/factorial.py
index 3569741..abaedd9 100755
--- a/factorial.py
+++ b/factorial.py
@@ -7,17 +7,22 @@
 
 
 def factorial(n):
-    # TODO Define your logic for factorial here
-    return # TODO!
+    prod = 1
+    for i in range(n):
+        prod = prod * (n - i)
+    return prod
+
 
 def test_factorial():
     assert factorial(1) == 1
-    # TODO: add more
+    assert factorial(4) == 24
+    assert factorial(0) == 1
+
 
 if __name__ == '__main__':
     # This is a way to determine either file was "executed", so if it was
     # imported (by e.g. pytest) as a library, we should not run code
     # below
-    nconditions = raw_input("Please enter number of conditions: ")
-    norders = factorial(nconditions)
-    print("Number of possible trial orders: " + str(norders)
+    nconditions = input("Please enter number of conditions: ")
+    norders = factorial(int(nconditions))
+    print("Number of possible trial orders: " + str(norders))