【解決方法】色違いの蹄鉄ですか？

Maximus horse wants to go to the party with his friends. He loves to keep up with the newest fashion trends, especially in wearing horseshoes, and now the latest fashion trends are wearing all horseshoes of different colors.

Maximus already has horseshoes, but probably some of them are the same color, so he needs to make shopping to buy the new horseshoes and to be pretty nice at the party. The horseshoe store offers many colors of horseshoes, and Maximus has enough money to buy any four of them. You need to help Maximus to determine the minimum number of horseshoes he needs to buy to wear four horseshoes of different colors to a party.

私が試したこと：

What I have tried:

<pre>Input Format

The first line contains four space-separated integers h1, h2, h3, h4 — the colors of horseshoes Valera has.

Constraints

(1 ≤ h1, h2, h3, h4 ≤ 109) Consider all possible colors indexed with integers.

Output Format

Print a single integer — the minimum number of horseshoes Valera needs to buy.

Sample Input 0

1 7 3 3
Sample Output 0

1
Sample Input 1

7 7 7 7
Sample Output 1

3