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

#define int ll
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 lc = 1, mxtail = 0;
    for(int i = 0; i < n; i++)
    {
        if(vis[find(i)]) continue;
        vis[find(i)] = 1;

        int s = sz[find(i)];

        vector<int> v(s);
        iota(all(v), 1);
        v[s - 1] = 0;

        map<vector<int>, int> mp;
        mp[v] = 1;
        int tot = 1;
        while(1)
        {
            auto t = v;
            for(auto &it : t) it = v[it];
            v = t;

            if(mp[v])
            {
                mxtail = max(mxtail, mp[v] - 1);
                lc = lcm(lc, tot - mp[v] + 1);
                break;
            }
            mp[v] = ++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;
}