#include <iostream>
#include <cstdlib>

using namespace std;

int main()
{
    int n;
    while (cin >> n)
    {
        int* mons = (int*)malloc(n * sizeof(int));
	for (int i = 0; i < n; i++)
	{
	    cin >> mons[i];
	    mons[i]--;
	}
	int* poss = (int*)malloc(n * sizeof(int));
	for (int i = 0; i < n; i++)
	{
	    poss[mons[i]] = i;
	}
	int swaps = 0;
	for (int i = 0; i < n; i++)
	{
	    if (mons[i] != i)
	    {
	        int postake = poss[i];
		int curmons = mons[i];
		mons[i] = i;
		mons[postake] = curmons;
		poss[i] = i;
		poss[curmons] = postake;
		swaps++;
	    }
	}
	cout << swaps << endl;
    }
    return 0;
}