N = int(input())
p = list(map(int, input().split()))

pos = [0] * N
ans = 0

for i in range(N):
    p[i] -= 1
    pos[p[i]] = i

for i in range(N):
    if p[i] != i:
        j = pos[i]
        p[i], p[j] = p[j], p[i]
        pos[p[i]], pos[p[j]] = pos[p[j]], pos[p[i]]
        ans += 1

print(ans)