Count Equal Adjacent Pairs

Source: Phước Hưng OJ

Version: Phuoc Hung OJ Extended

Problem

Given $a_1,\ldots,a_n$, count indices $i$ with $2\le i\le n$ and $a_i=a_{i-1}$.

Input

Line 1 contains $n$. Line 2 contains $a_1,\ldots,a_n$.

Output

Print the required integer answer.

Subtasks

Subtask 1 (20 points): $1\le n\le 50$; $|a_i|\le 100$.

Subtask 2 (30 points): $1\le n\le 5000$; $|a_i|\le 1000000$.

Subtask 3 (50 points): $1\le n\le 100000$; $|a_i|\le 1000000000$.

Example

Input

8
1 1 2 2 2 3 4 4

Output

4

Explanation

The values follow directly from the definitions and illustrate the valid index range of the array scan.