题目描述

Given any permutation of the numbers {0, 1, 2,..., N-1}, it is easy to sort them in increasing order.  But what if Swap(0, *) is the ONLY operation that is allowed to use?  For example, to sort {4, 0, 2, 1, 3} we may apply the swap operations in the following way:
Swap(0, 1) => {4, 1, 2, 0, 3}
Swap(0, 3) => {4, 1, 2, 3, 0}
Swap(0, 4) => {0, 1, 2, 3, 4}
Now you are asked to find the minimum number of swaps need to sort the given permutation of the first N nonnegative integers.

输入描述:

Each input file contains one test case, which gives a positive N (<=105) followed by a permutation sequence of {0, 1, ..., N-1}.  All the numbers in a line are separated by a space.

输出描述:

For each case, simply print in a line the minimum number of swaps need to sort the given permutation.

输入例子:

10 3 5 7 2 6 4 9 0 8 1

输出例子:

9