diff --git a/pystruct/models/graph_crf.py b/pystruct/models/graph_crf.py
index 81860e90..84ebeb81 100644
--- a/pystruct/models/graph_crf.py
+++ b/pystruct/models/graph_crf.py
@@ -101,7 +101,7 @@ def _set_size_joint_feature(self):
             else:
                 self.size_joint_feature = (
                     self.n_states * self.n_features
-                    + self.n_states * (self.n_states + 1) / 2)
+                    + self.n_states * (self.n_states + 1) // 2)
 
     def _get_edges(self, x):
         return x[1]