#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
long long res = 0;
void merge(vector<int> & v, int l, int r) {
	if (r-l <= 1) return;
	int mid = l + (r-l)/2;
	::merge(v, l, mid);
	::merge(v, mid, r);
	vector<int> tmp;
	int lId = l, rId = mid;
	for (int i = l; i < r; i++) {
		if ((lId < mid && v[lId] < v[rId]) || rId >= r)
			tmp.push_back(v[lId++]);
		else
			tmp.push_back(v[rId++]), res += 1;
	}
	for (int i = l; i < r; i++)
		v[i] = tmp[i-l];
	
}

int main() {
	ll n;
	ios::sync_with_stdio(0);
	while (cin >> n) {
		res = 0;
		vector<int> v(n),m(n+7);
		for (int i = 0; i < n; i++) 
			cin >> v[i];
		for (int i = 0; i < n; i++)
			m[v[i]] = i;
		for (int i = 0; i < n; i++) {
			if (i+1 != v[i]) {
				int bad = v[i];
				swap(v[i], v[m[i+1]]);
				swap(m[i+1], m[bad]);
				res ++;
			}
		}
		cout << res << endl;
	}
}