diff --git a/contracts/MerkleTreeWithHistory.sol b/contracts/MerkleTreeWithHistory.sol
index da1fdfa..5f5647b 100644
--- a/contracts/MerkleTreeWithHistory.sol
+++ b/contracts/MerkleTreeWithHistory.sol
@@ -23,12 +23,12 @@ contract MerkleTreeWithHistory {
 
   // the following variables are made public for easier testing and debugging and
   // are not supposed to be accessed in regular code
-  uint32 public constant ROOT_HISTORY_SIZE = 100;
-  bytes32[ROOT_HISTORY_SIZE] public roots;
-  uint32 public currentRootIndex = 0;
-  uint32 public nextIndex = 0;
   bytes32[] public filledSubtrees;
   bytes32[] public zeros;
+  uint32 public currentRootIndex = 0;
+  uint32 public nextIndex = 0;
+  uint32 public constant ROOT_HISTORY_SIZE = 100;
+  bytes32[ROOT_HISTORY_SIZE] public roots;
 
   constructor(uint32 _treeLevels) public {
     require(_treeLevels > 0, "_treeLevels should be greater than zero");