Use long long.

2023204/main.cpp

@@ -4,8 +4,7 @@
 // 'Natural count' is the name of the node when all the nodes in the tree is
 // alive. xxx_num denotes the count as the question described.
 
-// SEE ALSO:
-// branch 04_02 has a correct and more elegant implementation.
+// SEE ALSO BRANCH 04_02 WITH A CORRECT IMPLEMENTATION 
 
 int ans[200] = {0};
 long long dead_nodes_num[105] = {0};