n = int(input())
A = list(map(int, input().split()))

ans = 0
for i in range(n):
    if A[i] != i + 1:
        for j in range(i + 1, n):
            if A[j] == i + 1:
                ans += 1
                A[i], A[j] = A[j], A[i]
print(ans)