diff --git a/bootcamp/contrib/student_17.py b/bootcamp/contrib/student_17.py
new file mode 100644
index 0000000..afc4878
--- /dev/null
+++ b/bootcamp/contrib/student_17.py
@@ -0,0 +1,15 @@
+def is_prime(n: int) -> bool:
+    """
+    Check if a number is prime.
+    A prime num is greater than 1 and has no divisors other than 1 and itself.
+    Parameters:
+        n (int): The number to check.
+    Returns:
+        bool: True if the number is prime, False otherwise.
+    """
+    if n <= 1:
+        return False
+    for i in range(2, int(n**0.5) + 1):
+        if n % i == 0:
+            return False
+    return True
diff --git a/bootcamp/core/student_17.py b/bootcamp/core/student_17.py
index b904827..9495a3b 100644
--- a/bootcamp/core/student_17.py
+++ b/bootcamp/core/student_17.py
@@ -24,7 +24,7 @@ def count_substring(string, substring):
         left_bound = i
         right_bound = i + substring_length
         candidate_substring = string[left_bound:right_bound]
-        if candidate_substring == substring:
+        if candidate_substring.lower() == substring.lower():
             count += 1
 
     return count
diff --git a/bootcamp/core/tests/test_student_17.py b/bootcamp/core/tests/test_student_17.py
index 76ea70d..dd6be59 100644
--- a/bootcamp/core/tests/test_student_17.py
+++ b/bootcamp/core/tests/test_student_17.py
@@ -26,3 +26,12 @@ def test_count_substring_none():
     expected_count = 0
     observed_count = count_substring(test_string, test_substring)
     assert expected_count == observed_count
+
+
+def test_count_substring_case_sensitive():
+    test_string = "CGCTAGCGT"
+    test_substring = "cgc"
+
+    expected_count = 1
+    observed_count = count_substring(test_string, test_substring)
+    assert expected_count == observed_count