## Problem

There are `n`

cities labeled from `1`

to `n`

. You are given the integer `n`

and an array `connections`

where `connections[i] = [xi, yi, costi]`

indicates that the cost of connecting city `xi`

and city `yi`

(bidirectional connection) is `costi`

.

Return *the minimum cost to connect all the*

`n`

*cities such that there is at least one path between each pair of cities*. If it is impossible to connect all the

`n`

cities, return `-1`

,The **cost** is the sum of the connections’ costs used.