#include <iostream>

using namespace std;

int main(){
	ios::sync_with_stdio(false);
	int n=0;
	int N[200001];
	int M[200001];
	while(cin>>n){
		int a=0;
		for(int i=1;i<=n;i++){
			cin>>N[i];
			//N[i]--;
			M[N[i]] = i;
		}

		for(int i=1;i<=n;i++){
			if(N[i]!=i){
				a++;
				int temp = N[i];
				int pos_temp = M[i];

				//N[i] = i;
				N[pos_temp] = temp;
				N[i] = i;

				//M[i] = i;
				M[temp] = pos_temp;
				M[i]=i;

				//cout<<"vymienam "<<i<<" s "<<temp<<endl;
				//for(int j=1;j<=n;j++) cout<<N[j]<<" ";
				//cout<<endl;
			}
		}
		cout<<a<<endl;
	}
	return 0;
}