#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod = 1e9 + 7;
ll t = 1,n,m,k,q,l,r,a[109],b[109],c,u,v,x,y,z;
string s;
struct st{ll x,y; /*bool operator < (const st &a) const{return x < a.x;};*/};
bool cmp(const st &a,const st &b){return a.x < b.x;}
inline ll read(){
	ll s = 0,w = 1;
	char ch = getchar();
	while (ch > '9' || ch < '0'){ if (ch == '-') w = -1; ch = getchar();}
	while (ch <= '9' && ch >= '0') s = (s << 1) + (s << 3) + (ch ^ 48),ch = getchar();
	return s * w;
}
ll qp(ll x,ll y){
	ll a = 1,b = x;
	while (y){
		if (y & 1) a = a * b % mod;
		b = b * b % mod,y >>= 1;
	}
	return a;
}
int main(){//t = read();
while (t --){
	n = read();
	ll cnt = 0;
	for (ll i = 1;i <= n;i += 1) a[i] = read(),b[a[i]] = i;
	for (ll i = 1;i <= n;i += 1) if (a[i] != i){
		ll qwq = a[i];
		swap(a[i],a[b[i]]);
		swap(b[i],b[qwq]);
		cnt += 1;
	}
	printf("%lld",cnt);
}
	return 0;
}