Given a string text and an array of strings words, return a list of all index pairs [i, j] such that the substring text[i...j] is present in words.

Return the pairs [i, j] in sorted order, first by the value of i, and if two pairs have the same i, by the value of j.

Constraints:

• $1 \leq$ text.length $\leq 100$

• $1 \leq$ words.length $\leq 20$

• $1 \leq$ ...