mod = 998244353
eps = 10**-9


def main():
    import sys
    input = sys.stdin.readline

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

    idx = {p: i for i, p in enumerate(P)}
    i0 = idx[0]
    l = r = i0
    ans = 1
    for p in range(1, N):
        i = idx[p]
        if i < l:
            l = i
        elif i > r:
            r = i
        else:
            ans = (ans * (r - l + 1 - p))%mod
    print(ans)


if __name__ == '__main__':
    main()