#include <bits/stdc++.h>
const int N = 202;
int f[N];
std::vector<int> G[N], G2[N];
long long gcd(long long x, long long y) { return x ? gcd(y % x, x) : y; }
int pre[N], dfs_clock, S[N], top;
int scc[N], sccno;
int num[N];
int dfs(int u) {
  int lowu = pre[u] = ++dfs_clock;
  S[top++] = u;
  for (int v : G[u]) {
    if (!pre[v]) {
      lowu = std::min(lowu, dfs(v));
    } else if (!scc[v]) {
      lowu = std::min(lowu, pre[v]);
    }
  }
  if (pre[u] == lowu) {
    sccno++;
    for (int v = -1; v != u;) {
      v = S[--top];
      scc[v] = sccno;
      num[sccno]++;
    }
  }
  return lowu;
}
int dfs2(int u) {
  int ret = 0;
  for (int v : G2[u]) {
    if (pre[v] == -1) {
      ret = std::max(ret, dfs2(v) + 1);
    } else {
      ret = std::max(ret, pre[v] + 1);
    }
  }
  return pre[u] = ret;
}
int main() {
  int n;
  srand(time(NULL));
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", f + i);
    G[i].push_back(f[i]);
  }
  for (int i = 1; i <= n; i++)
    if (!pre[i]) {
      dfs(i);
    }
  for (int i = 1; i <= n; i++) {
    for (int v : G[i]) {
      if (scc[v] != scc[i]) {
        G2[scc[i]].push_back(scc[v]);
      }
    }
  }
  long long k = 1;
  for (int i = 1; i <= sccno; i++) {
    k = k / gcd(k, num[i]) * num[i];
  }
  memset(pre, -1, sizeof pre);
  int max = 0;
  for (int i = 1; i <= sccno; i++)
    if (pre[i] == -1) {
      int res = dfs2(i);
      max = std::max(res, max);
    }
  int res = max;
  if (res > k) k = (res / k + (res % k != 0)) * k;
  printf("%I64d\n", k);
  return 0;
}
