#include <cstdlib>
#include <locale>
#include <bits/stdc++.h>
using namespace std;

/*
 * 
 */
int main(int argc, char** argv) {

    std::ios::sync_with_stdio(false);
    int a;
    while(cin >> a){
        vector<int> v;
        int * idx = new int[a];
        for(int i = 0; i < a; i++){
            int tmp;
            cin >> tmp;
            v.push_back(tmp);
            idx[tmp-1] = i;  
        }
 
        int pocetKroku = 0;
        for(int i = 0; i < a; i++){
            if(v[i] != i+1){
                int swapper = v[i],swapperIdx = idx[i];
                v[i] = v[idx[i]];
                v[idx[i]] = swapper;
                
                idx[i] = idx[swapper-1];
                idx[swapper-1] = swapperIdx;
                pocetKroku++;
            }
            
        }
        cout << pocetKroku << endl;
    }
    
    return 0;
}