diff --git a/leap_year.py b/leap_year.py
old mode 100644
new mode 100755
index 6a1002b..5fdea2b
--- a/leap_year.py
+++ b/leap_year.py
@@ -4,7 +4,38 @@ def is_leap_year(year: int):
     return year % 4 == 0 and year % 100 != 0 or year % 400 == 0
 
 
+def get_day_of_month(year, month: int) -> int:
+    match month:
+        case 1 | 3 | 5 | 7 | 8 | 10 | 12:
+            return 31
+        case 4 | 6 | 9 | 11:
+            return 30
+        case 2 if is_leap_year(year):
+            return 29
+        case 2:
+            return 28
+        case _:
+            raise Exception(f"invalid month: {month}")
+
+
+def get_day_of_month2(year, month: int) -> int:
+    if [1, 3, 5, 7, 8, 10, 12].__contains__(month):
+        return 31
+    elif [4, 6, 9, 11].__contains__(month):
+        return 30
+    elif month == 2 and is_leap_year(year):
+        return 29
+    elif month == 2:
+        return 28
+    else:
+        raise Exception(f"invalid month: {month}")
+
+
 if __name__ == "__main__":
     print(1582, is_leap_year(1582))
     print(2000, is_leap_year(2000))
     print(2100, is_leap_year(2100))
+
+    print(2000, 1, '->', get_day_of_month(2000, 1), get_day_of_month2(2000, 1))
+    print(2000, 2, '->', get_day_of_month(2000, 2), get_day_of_month2(2000, 2))
+    print(2001, 2, '->', get_day_of_month(2001, 2), get_day_of_month2(2001, 2))