def solve(a):
    tomove = []
    n = len(a)
    for i in range(n-1, -1, -1):
        if n != a[i]:
            tomove.append(a[i])
        else:
            n -= 1
    return len(tomove)


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

print(solve(a))