diff --git a/src/MultiSet.java b/src/MultiSet.java
new file mode 100644
index 0000000..a25d46d
--- /dev/null
+++ b/src/MultiSet.java
@@ -0,0 +1,11 @@
+public abstract class MultiSet {
+    public boolean add()
+    {
+        
+    }
+
+    public void remove()
+    {
+
+    }
+}
diff --git a/src/Tree.java b/src/Tree.java
index 458a7c7..c43c782 100644
--- a/src/Tree.java
+++ b/src/Tree.java
@@ -1,2 +1,3 @@
 public class Tree {
+
 }