N = int(input())
P = list(map(int, input().split()))
Q = sorted(P)


ans = 0

for i in range(1, N + 1):
    j = P.index(i)
    if j != i - 1:
        ans += 1
        P[j], P[i - 1] = P[i - 1], P[j]

print(ans)