diff --git a/students_submissions/gcd_crh35.py b/students_submissions/gcd_crh35.py
new file mode 100644
index 0000000..9b9618a
--- /dev/null
+++ b/students_submissions/gcd_crh35.py
@@ -0,0 +1,31 @@
+def gcd(a: int, b: int) -> int:
+
+    if isinstance(a, bool) or isinstance(b, bool) or not isinstance(a, int) or not isinstance(b, int):
+        print("Error: gcd(a, b) two integers are required.")
+        return None
+
+    if a == 0 and b == 0:
+        print("Error: gcd(0, 0) is undefined.")
+        return None
+
+    a = abs(a)
+    b = abs(b)
+
+    if b == 0:
+        return a
+
+    return gcd(b, a % b)
+
+
+print(gcd(20, 8))
+print(gcd(100, 25))
+print(gcd(101, 10))
+print(gcd(13, 7))
+print(gcd(17, 3))
+print(gcd(54, -24))
+print(gcd(-54, 24))
+print(gcd(0,9))
+print(gcd(9,0))
+print(gcd(18, 18))
+print(gcd(2.5, 2))
+