The NumberEater is a famous monster from Byteland. It eats numbers, but it is very picky: each day its meal must be unique. The monster is given a sequence of integers (a_n). It chooses the starting and ending positions of a meal -i and j (1 ≤ i ≤ j ≤ n) - and prepares a meal that consists of elements a_i, a_i+1, …, a_j. The monster considers two meals [i₁,j₁] and [i₂,j₂] identical if the sets of numbers that they contain are the same; in other words:</p>

{a_k : i₁ ≤ k ≤ j₁} = {a_k : i₂ ≤ k ≤ j₂}

Help NumberEater and count the number of different meals that it can prepare using only the sequence a.

입력 형식

The first line of the input contains one integer n (1 ≤ n ≤ 500), the length of the sequence a. The following n lines contain values of elements of the sequence. Each of them is at least 1 and at most 500.

출력 형식

The first and only line of the output should contain the number of different meals that NumberEater can prepare.</p>

예제 입력

6
1
2
3
1
2
3

예제 출력

7