#include <bits/stdc++.h>

#define el '\n'
#define Beevo ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

typedef long long ll;
typedef long double ld;

using namespace std;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

void testCase() {
    int n;
    cin >> n;

    int p[n + 1], q[n + 1];
    for (int i = 1; i <= n; i++)
        cin >> p[i], q[i] = p[i];

    ll mx = 1;
    ll l = 1, cnt;
    vector<bool> vis(n + 1);
    for (int i = 1; i <= n; i++) {
        if (vis[i])
            continue;

        vector<int> indices = {i}, vals = {p[i]};
        while (p[indices.back()] != i)
            indices.push_back(p[indices.back()]), vals.push_back(p[indices.back()]), vis[indices.back()] = 1;

        cnt = 0;
        set<vector<int>> visSt;
        vector<int> cur = vals, lst;
        while (1) {
            if (visSt.find(cur) != visSt.end())
                break;

            cnt++, visSt.insert(cur), lst = cur, cur.clear();

            for (auto &j: indices)
                q[j] = p[p[j]], cur.push_back(q[j]);

            for (auto &j: indices)
                p[j] = q[j];
        }

        if (lst == cur)
            mx = max(mx, cnt);
        else
            l = 1LL * l * cnt / __gcd(l, cnt);
    }

    cout << mx - 1 + l;
}

signed main() {
    Beevo

    int t = 1;
//    cin >> t;

    while (t--)
        testCase();
}