#include <bits/stdc++.h>
using namespace std;
const int MAXN = 207;
int n, f[MAXN];
long long mmc_atual = 1;
vector<int> folhas, Gr[MAXN];
bool in_cycle[MAXN], mrk[MAXN];
int marca_ciclo(int u) {
  if (in_cycle[u]) return 0;
  in_cycle[u] = true;
  return 1 + marca_ciclo(f[u]);
}
void dfsr(int u) {
  mrk[u] = true;
  bool flag = true;
  for (int i = 0; i < (int)Gr[u].size(); i++) {
    int viz = Gr[u][i];
    flag = false;
    if (mrk[viz]) continue;
    dfsr(viz);
  }
  if (flag) folhas.push_back(u);
}
int dfs(int u) {
  if (in_cycle[u]) return 0;
  return 1 + dfs(f[u]);
}
long long mdc(long long a, long long b) { return (a == 0) ? b : mdc(b % a, a); }
long long mmc(long long a, long long b) { return (a / mdc(a, b)) * b; }
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> f[i];
    Gr[f[i]].push_back(i);
  }
  long long ans = 1;
  long long mx_chain = 0;
  for (int i = 1; i <= n; i++) {
    if (!mrk[i]) {
      int turtoise = i;
      int hare = i;
      do {
        turtoise = f[turtoise];
        hare = f[f[hare]];
      } while (turtoise != hare);
      int tam_ciclo = marca_ciclo(hare);
      mmc_atual = mmc(mmc_atual, (long long)tam_ciclo);
      dfsr(hare);
    }
  }
  for (int i = 0; i < (int)folhas.size(); i++) {
    int tam_chain = dfs(folhas[i]);
    mx_chain = max(mx_chain, (long long)tam_chain);
  }
  if (mx_chain % mmc_atual != 0)
    mx_chain = (mx_chain - mx_chain % mmc_atual) + mmc_atual;
  ans = max(mmc_atual, mx_chain);
  cout << ans << endl;
}
