#include <iostream>
#include <unordered_map>
using namespace std;

int main() {
    int N;
    cin >> N;
    int P[N];
    unordered_map<int, int> pos;
    for (int i = 0; i < N; i++) {
        cin >> P[i];
        pos[P[i]] = i;
    }
    int swaps = 0;
    for (int i = 0; i < N; i++) {
        if (P[i] != i+1) {
            int j = pos[i+1];
            swap(P[i], P[j]);
            pos[P[i]] = i;
            pos[P[j]] = j;
            swaps++;
        }
    }
    cout << swaps << endl;
    return 0;
}