917 B | 917 chars
import sys
from math import sqrt, pi, sin, factorial, ceil, floor
from datetime import datetime, timedelta
sys.setrecursionlimit(10**7)
BLANK = " "
# inp = input
inp = lambda : sys.stdin.readline().rstrip()
mii = lambda x = BLANK : [*map(int,inp().split(x))]
mfi = lambda x = BLANK : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
l = []
cnt = 0
visited = []
def gcd(a, b):
return gcd(b, a % b) if b > 0 else a
def f(i):
global visited, cnt, l
if visited[i]:
return
cnt += 1
visited[i] = 1
f(l[i])
def solve():
global l, visited, cnt
n = ii()
l = mii()
visited = [0] * n
for i in range(n):
l[i] -= 1
ans = 1
for i in range(n):
cnt = 0
f(l[i])
if(cnt > 0):
ans = cnt * ans // gcd(ans, cnt)
p(ans)
if __name__ == "__main__":
tc = 1
for t in range(1, tc+1):
ret = solve()