diff --git a/pandas_and_tidying_ex3.py b/pandas_and_tidying_ex3.py
index e69de29..38b1f01 100644
--- a/pandas_and_tidying_ex3.py
+++ b/pandas_and_tidying_ex3.py
@@ -0,0 +1,5 @@
+x = pd.merge(sampleruns.reset_index(drop=True),
+             mutations.reset_index(drop=True),
+             left_on=['Strain ID', 'Population', 'Generation'],
+             right_on=['Strain ID', 'Population', 'Generation'],
+             how='left')