Minimize Expression with Parentheses

You are given a string expression that represents a positive arithmetic expression containing exactly one plus sign '+'. The string contains only digits and the plus sign.

Insert exactly one left parenthesis somewhere to the left of the plus sign and exactly one right parenthesis somewhere to the right of the plus sign. After inserting the parentheses, evaluate the resulting expression under the rule that any value immediately outside the parentheses is multiplied with the value inside.

Return the parenthesized expression that produces the minimum possible numeric result.

For example, if expression = "1639+5628", then 16(39+5)628 is a valid candidate because the parts outside the parentheses are multiplied with the parenthesized sum.