A freight depot holds a queue of shipping containers waiting to be logged into the system, each stamped with a positive integer tag. The logging system rejects the whole batch if any two remaining containers share a tag, so the yard operator repeatedly clears containers from the FRONT of the queue: each clearance operation removes exactly three containers from the front (or all remaining containers, if fewer than three are left). The operator stops as soon as every container still in the queue carries a tag different from every other remaining container (an empty queue trivially satisfies this). Given the initial queue, compute the minimum number of clearance operations needed.

Input format

Line 1: an integer n, the number of containers. Line 2: n space-separated integers a_1 ... a_n, the tag of each container from the front of the queue to the back.

Output format

Print a single integer: the minimum number of clearance operations required.

Constraints

• 1 <= n <= 100
• 1 <= a_i <= 100

5
1 2 3 4 1

1

7
5 5 5 5 5 5 5

2