import sys

def solve():
    N = int(input())
    A = [int(i) for i in input().split()]

    s = A.index(N)
    nxt = N - 1

    while s > 0:
        for i in range(s - 1, -1, -1):
            if A[i] == nxt:
                s = i
                nxt -= 1
                break
        else:
            s = 0

    print(nxt)

def debug(x, table):
    for name, val in table.items():
        if x is val:
            print('DEBUG:{} -> {}'.format(name, val), file=sys.stderr)
            return None


if __name__ == '__main__':
    solve()