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# 1319. Number of Operations to Make Network Connected

## Description

There are `n`

computers numbered from `0`

to `n-1`

connected by ethernet cables `connections`

forming a network where `connections[i] = [a, b]`

represents a connection between computers `a`

and `b`

. Any computer can reach any other computer directly or indirectly through the network.

Given an initial computer network `connections`

. You can extract certain cables between two directly connected computers, and place them between any pair of disconnected computers to make them directly connected. Return the *minimum number of times* you need to do this in order to make all the computers connected. If it's not possible, return -1.

**Example 1:**

Input:n = 4, connections = [[0,1],[0,2],[1,2]]Output:1Explanation:Remove cable between computer 1 and 2 and place between computers 1 and 3.

**Example 2:**

Input:n = 6, connections = [[0,1],[0,2],[0,3],[1,2],[1,3]]Output:2

**Example 3:**

Input:n = 6, connections = [[0,1],[0,2],[0,3],[1,2]]Output:-1Explanation:There are not enough cables.

**Example 4:**

Input:n = 5, connections = [[0,1],[0,2],[3,4],[2,3]]Output:0

**Constraints:**

`1 <= n <= 10^5`

`1 <= connections.length <= min(n*(n-1)/2, 10^5)`

`connections[i].length == 2`

`0 <= connections[i][0], connections[i][1] < n`

`connections[i][0] != connections[i][1]`

- There are no repeated connections.
- No two computers are connected by more than one cable.