#!/usr/bin/env python3
import collections
import functools
import operator

N = int(input())
a = [0] + list(map(int, input().split()))
rest = list(range(len(a)))
loop = collections.defaultdict(int)
while True:
    if len(rest) == 0:
        break
    now = rest[0]
    count = 0
    while True:
        rest.remove(now)
        now = a[now]
        count += 1
        if now not in rest:
            loop[count] += 1
            break
for k, v in loop.items():
    if k % 2 == 1 or v % 2 == 0:
        continue
    print("No")
    exit()
print("Yes")