#include <bits/stdc++.h>

#define pb push_back
#define F first
#define S second
#define MP make_pair
#define all(x) x.begin(),x.end()
#define Hagry ios::sync_with_stdio(false);cout.tie(NULL);cin.tie(NULL);

using namespace std;
using ll = long long;
using pi = pair<int, int>;
using vi = vector<int>;
using vpi = vector<pair<int, int>>;
using vvi = vector<vector<int>>;

const int OO = 1e9 + 5;
const int N = 2e5 + 5;
const ll MOD = 1e9 + 7;

ll powmod(ll x, ll y) {
    x %= MOD;
    ll ans = 1;
    while (y) {
        if (y & 1) ans = ans * x % MOD;
        x = x * x % MOD;
        y >>= 1;
    }
    return ans;
}

ll add(ll a, ll b) {
    a += b;
    if (a >= MOD) a -= MOD;
    return a;
}

ll sub(ll a, ll b) {
    a -= b;
    if (a < 0) a += MOD;
    return a;
}

ll mul(ll a, ll b) { return a * b % MOD; }

ll inv(ll a) { return powmod(a, MOD - 2); }
void TC() {
    int n;
    cin >> n;

    int nxt[n + 1];
    nxt[0] = 0;
    for (int i = 1; i <= n; ++i)
        cin >> nxt[i];

    vi len(n + 1), vis(n + 1), in(n + 1), cycID(n + 1);
    ll ans = 1;
    int cycNum = 0;
    for (int i = 1; i <= n; ++i) {
        ++in[nxt[i]];
        if (vis[i])continue;

        stack<int> st;
        st.push(i);
        while (!vis[st.top()]) {
            vis[st.top()] = i;
            st.push(nxt[st.top()]);
        }

        int prv = -1;
        if (vis[st.top()] == i) {
            ++cycNum;
            int start = st.top();
            prv = st.top();
            st.pop();
            while (!st.empty() && vis[st.top()] == i) {
                cycID[st.top()] = cycNum;
                prv = st.top();
                st.pop();
                if (prv == start) break;
            }
        }
        if (!st.empty()) {
            if (prv == -1) {
                prv = st.top();
                st.pop();
            }
            while (!st.empty()) {
                cycID[st.top()] = cycID[prv];
                len[st.top()] = len[prv] + 1;
                prv = st.top();
                st.pop();
            }
        }

    }

    vector<ll> ways(cycNum + 1, 1);
    for (int i = 1; i <= n; ++i) {
        assert(cycID[i]);
        if (in[i] == 0)
            ways[cycID[i]] = mul(ways[cycID[i]], add(len[i], 1));
    }
    for (int i = 1; i <= cycNum; ++i)
        ans = mul(ans, add(ways[i],1));

    ans = sub(ans, 1);
    cout << ans;
}

int32_t main() {
#ifndef ONLINE_JUDGE
    freopen("input.in", "r", stdin);
    freopen("output.out", "w", stdout);
#endif
    Hagry
    int t = 1;
//    cin >> t;
    while (t--) {
        TC();
        cout << '\n';
    }
    return 0;
}