diff --git a/internal/ceres/block_structure.h b/internal/ceres/block_structure.h
index b5218c0..d49d7d3 100644
--- a/internal/ceres/block_structure.h
+++ b/internal/ceres/block_structure.h
@@ -40,6 +40,7 @@
 
 #include <cstdint>
 #include <vector>
+
 #include "ceres/internal/port.h"
 
 namespace ceres {