**There are n towns numbered 1 to n, and m roads connecting them. Arrays a and b are given such that road i connects towns a[i] and b[i]. Your task is to return an array of size m whose i-th element denotes the least number of roads that would be used in traveling from town 1 to town n when the i-th road cannot be used in the traversal. Return -1 as the i-th element if it is impossible to travel from town 1 to town n without using the i-th road. Graph is Undirected and all pairs (a[i] , b[i]) are distinct.**

$$$Constraints$$$

$$$2 \le n \le 300$$$

$$$1 \le m \le n*(n-1)$$$

$$$ a[i] != b[i] $$$

$$$ 1 \le a[i] , b[i] \le n$$$

I tried this code but the time complexity will be $$$O(m{^2})$$$.

**code**