diff --git a/.idea/misc.xml b/.idea/misc.xml
index d15472f..045943f 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_18" default="true" project-jdk-name="openjdk-18" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_20" default="true" project-jdk-name="openjdk-18" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/out" />
   </component>
 </project>
\ No newline at end of file
diff --git a/src/MyMath.java b/src/MyMath.java
index 7da9a29..32b9ede 100644
--- a/src/MyMath.java
+++ b/src/MyMath.java
@@ -2,6 +2,33 @@
 
 public class MyMath {
 
+    public static int gcf(int a, int b) {
+        while (b != 0) {
+            if (a > b) {
+                int c = b;
+                b = a % b;
+                a = c;
+            } else {
+                b = b % a;
+            }
+        }
+        return a;
+    }
+
     public static void main(String[] args) {
+        Scanner s = new Scanner(System.in);
+        String inputOne, inputTwo = null;
+        String message1 = "Give me a %snumber please (Q to quit): ", message2 = "Give me a second %snumber please (Q to quit): ";
+        System.out.print(String.format(message1, ""));
+        while (!(inputOne = s.nextLine()).equals("Q")) {
+            if (inputTwo == null) {
+                inputTwo = inputOne;
+                System.out.print(String.format(message2, ""));
+                continue;
+            }
+            System.out.printf("GCF of %s and %s is %d%n", inputOne, inputTwo, gcf(Integer.parseInt(inputOne), Integer.parseInt(inputTwo)));
+            System.out.print(String.format(message1, ""));
+            inputTwo = null;
+        }
     }
 }