Graphic: Rerouting problem test in python language

Your company has N servers. The information flows from one server to another through a connection.

If the information flows from server i to server j, then connection(i) = j. It's possible for some server connection(i) = i, meaning information doesn't flow further.

You are given an array connection consisting of N integers. You are tasked with making minimum number of changes to connection array values so that the information from all server can reach at exactly one server in the whole network, where it terminates.

If node X is terminal server, then connection_i = X.

Input Format
First line contains an integer N, no of servers in the network.

Second line contains N integers, i^th of which is connection_i.

Constraints

• 1 <= N <= 3*10⁵
• 1 <= connection_i <= N

Output Format
An integer representing minimum number of changers required.

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Sample Input 0

5
2 3 4 1 5

Sample Output 0

1

Explanation 0

We can choose node 5 as our terminal server and connect 4 -> 1 edge to 4->5. Our modified connection array becomes {2,3,4,5,5} after making just 1 update.

Sample Input 1

4
1 2 3 4

Sample Output 1

3

Explanation 1

We can select 1 as our terminal server and connect reset of the nodes to 1. The modified connection array becomes {1,1,1,1}.

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