Problem Description

You are given a sequence \(a_1, a_2, \ldots, a_n\). You can perform several operations on this sequence.

Suppose the length of the sequence before an operation is \(m\). During an operation, you can choose an integer \(i\) such that \(1 \le i \le m - 1\) and \(a_i \ne a_{i + 1}\). You then delete \(a_{i + 1}\) and set the value of \(a_i\) to any integer.

Determine the maximum number of operations you can perform.

Input Format

The first line contains a positive integer \(n\), representing the initial length of the sequence.

The second line contains \(n\) positive integers \(a_1, a_2, \ldots, a_n\).

Output Format

A single line containing a non-negative integer, representing the maximum number of operations that can be performed.

Sample Input and Output

Sample Input #1

2
1 2

Sample Output #1

1

Sample Input #2

3
1 1 1

Sample Output #2

0

Sample Input #3

4
1 1 45 14

Sample Output #3

3

Notes

Sample Explanation #1

You can choose \(i = 1\), delete \(a_2\), and set the value of \(a_1\) to 3. Now \(a = [3]\), and no further operations can be performed. Thus, the answer is 1.

Sample Explanation #2

No operations can be performed, so the answer is 0.

Data Range

This problem uses batched testing and has subtask dependencies enabled.

For all data, \(1 \le n \le 10^5\) and \(1 \le a_i \le 10^9\).

见题面 Input 部分

见题面 Output 部分