#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;
int main()
{
	ios_base::sync_with_stdio(false);
	int numberOfRooms;
	int numberOfSwaps = 0;
	vector<int> vstup;
	vstup.resize(2 * 100000);
	int otherRoom;
	while (cin >> numberOfRooms)
	{
		numberOfSwaps = 0;
		for (int i = 0; i < numberOfRooms; i++)
		{
			cin >> vstup[i];
		}
		for (int i = 0; i < numberOfRooms; i++)
		{
			if (vstup[i] != (i + 1)) 
			{
				numberOfSwaps++;
				otherRoom = vstup[i];
				std::swap(vstup[i], vstup[otherRoom -1]);
				i--;
			}
		}
		
		cout << numberOfSwaps << "\n";
	}
    return 0;
}