#include<cstdio>#include<cstdlib>#include<iostream>#include<cstring>#include<cmath>#include<queue>#include<set>#include<algorithm>using namespace std;#define REP(x, y) for(int x = 0; x < y; x++)#define DWN(x, y) for(int x = y-1; x > -1; x--)const int maxn = 1e3 + 10;int num[maxn];bool flag[maxn];int gcd(int a, int b){ return b ? gcd(b, a%b) : a;}int lcm(int a, int b){ return a*b/gcd(a, b);}int main(){ int n; while(scanf("%d", &n)!=EOF) { for(int i = 1; i <= n; i++)scanf("%d", &num[i]); memset(flag, 0, n+1); int ans = 1; for(int i = 1; i <= n; i++) { if(flag[i]) continue; int len = 0, u = i; do { len++; flag[u] = true; u = num[u]; }while(!flag[u]); ans = lcm(ans, len); } printf("%dn", ans); } return 0;}
