diff --git a/phasetool.py b/phasetool.py
index 1e9ec10b57fc9b3521389671cead5768df80687a..8352bbc26b906abab7719523dfd2cd6784f00812 100644
--- a/phasetool.py
+++ b/phasetool.py
@@ -146,7 +146,7 @@ class Annotation:
                 marks[x] = 0
                 prev = 0
             else:
-                marks[x] = prev
+                prev = marks[x]
         
         return marks, relations