You are installing a billboard and want it to have the largest height. The billboard will have two steel supports, one on each side. Each steel support must be an equal height.

You have a collection of `rods`

which can be welded together. For example, if you have rods of lengths 1, 2, and 3, you can weld them together to make a support of length 6.

Return the largest possible height of your billboard installation. If you cannot support the billboard, return 0.

**Example 1:**

Input:[1,2,3,6]Output:6Explanation:We have two disjoint subsets {1,2,3} and {6}, which have the same sum = 6.

**Example 2:**

Input:[1,2,3,4,5,6]Output:10Explanation:We have two disjoint subsets {2,3,5} and {4,6}, which have the same sum = 10.

**Example 3:**

Input:[1,2]Output:0Explanation:The billboard cannot be supported, so we return 0.

**Note:**

`0 <= rods.length <= 20`

`1 <= rods[i] <= 1000`

`The sum of rods is at most 5000.`