Mafija

Mafia is a social game played frequently by high school
competitors in informatics on summer and winter camps and
national competitions, usually very late at night, drinking
various fruit sodas. This game is not about winning, it’s about
~~los~~ taking part, like in competitions.

To solve this task, you don’t need to know the rules of mafia: all you need to know is that some of the players are “mobsters” and the rest are “civilians”. The mobsters know who is who, but the civilians don’t. The civilians are trying to figure out who the mobsters are during the game.

In the current round of the game, out of $N$ surviving players so far, each one
has accused *exactly one* other player saying that he is
the mobster. *The civilians were only guessing* and
*the mobsters have accused civilians*, pretending to
know nothing.

Not knowing who the mobsters are, but knowing who accused
whom, determine *the maximum possible number of
mobsters* among these players!

The first line of input contains the integer $N$ ($2 \leq N \leq 500\, 000$), the number of players. The players are labeled with integers from $1$ to $N$.

The $K$-th line of input, out of the following $N$ lines, contains the label of the player accused by the player $K$. (No player can accuse themselves).

The first and only line of output must contain the maximum possible number of mobsters.

Sample Input 1 | Sample Output 1 |
---|---|

3 2 1 1 |
2 |

Sample Input 2 | Sample Output 2 |
---|---|

3 2 3 1 |
1 |

Sample Input 3 | Sample Output 3 |
---|---|

7 3 3 4 5 6 4 4 |
4 |