#include<bits/stdc++.h>
#define ll long long
#define all(a) (a).begin(),(a).end()
using namespace std;

const int mod = 1e9 + 9;
const int p = 2333;
const int N = 1e5 + 10;

int n;
int fa[N], sz[N];

int find(int x){
    return x == fa[x] ? x : fa[x] = find(fa[x]);
}

void merge(int x, int y)
{
    x = find(x);
    y = find(y);
    if(x == y) return;
    if(sz[x] > sz[y]) swap(x, y);
    fa[x] = y;
    sz[y] += sz[x];
}

void solve()
{
    cin >> n;
    vector<int> a(n);
    for(int i = 0; i < n; i++) cin >> a[i], a[i]--;

    for(int i = 0; i < n; i++) fa[i] = i, sz[i] = 1;
    for(int i = 0; i < n; i++) merge(i, a[i]);

    vector<int> vis(n);
    int mxtail = 0;
    for(int i = 0; i < n; i++)
    {
        if(vis[find(i)]) continue;
        vis[find(i)] = 1;

        int s = sz[find(i)];

        int tail = 0;
        while(s)
        {
            if(s % 2) break;
            s /= 2;
            tail++;
        }
        mxtail = max(mxtail, tail);

        // cerr << sz[find(i)] << ' ' << tail << '\n';
    }

    // cerr << mxtail << '\n';

    for(int i = 1; i <= mxtail; i++)
    {
        auto t = a;
        for(auto &it : t) it = a[it];
        a = t;
    }

    ///////////////////////////////////////////////////////////////////////////////////

    vector<int> SZ(n + 1);
    for(auto &it : vis) it = 0;
    for(int i = 0; i < n; i++) fa[i] = i, sz[i] = 1;
    for(int i = 0; i < n; i++) merge(i, a[i]);
    int lc = 1;
    for(int i = 0; i < n; i++)
    {
        if(sz[find(i)] == 1 || SZ[sz[find(i)]]) continue;
        
        int s = sz[find(i)];        
        vector<int> v(s);
        iota(all(v), 1);
        v[s - 1] = 0;

        map<int, int> mp;
        int tot = 1;
        unsigned ll h = 0;
        for(auto &it : v) h = h * p + it;
        mp[h] = 1;
        while(1)
        {
            auto t = v;
            for(auto &it : t) it = v[it];
            v = t;
            h = 0;
            for(auto &it : v) h = h * p + it;

            if(mp[h])
            {
                int len = tot - mp[h] + 1;
                SZ[s] = len;
                lc = lcm(lc, len);
                break;
            }
            mp[h] = ++tot;
        }
    }

    cout << lc + mxtail;
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);cout.tie(nullptr);
    int t = 1;
    //cin >> t;
    while(t--) solve();
    return 0;
}