diff --git a/.idea/misc.xml b/.idea/misc.xml
index d15472f..5ad49fe 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_X" default="true" project-jdk-name="openjdk-20 (2)" 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..2a7063d 100644
--- a/src/MyMath.java
+++ b/src/MyMath.java
@@ -1,7 +1,35 @@
 import java.util.Scanner;
 
 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 input1, input2 = null;
+        String message = "Give me a %snumber (Q to quit): ";
+        System.out.print(String.format(message, ""));
+        while(!(input1 = s.nextLine()).equals("Q")) {
+            if(input2 == null) {
+                input2 = input1;
+                System.out.print(String.format(message, "second "));
+                continue;
+            }
+            System.out.printf("GCF of %s and %s is %d%n", input1, input2,
+                    gcf(Integer.parseInt(input1), Integer.parseInt(input2)));
+
+            System.out.print(String.format(message, ""));
+            input2 = null;
+        }
     }
 }