n = int(input())
p = list(map(int,input().split()))
for i in range(n):
    p[i] -= 1
    
from collections import *
d = defaultdict(int)

for i in range(n):
    d[p[i]] = i #インデックスを保持
    
ans = 0
for i in range(n):
    #print(p)
    if d[i] == i:
        continue
    ind = d[i]
    #print(ind,"ind")
    d[p[i]] = ind
    d[i] = i
    p[ind] = p[i]
    p[i] = i
    ans += 1
    
print(ans)