Given is an integer sequence D_1,...,D_N of N elements. Find the number, modulo 998244353, of trees with N vertices numbered 1 to N that satisfy the following condition:    * For every integer i from 1 to N, the distance between Vertex 1 and Vertex i is D_i.
#input = sys.stdin.readline
def inpl(): return list(map(int, input().split()))
print((int(input())-1)//2)
from collections import Counter
import sys
input = sys.stdin.readline
def inpl(): return list(map(int, input().split()))

MOD = 998244353
N= int(input())
D = inpl()
C = Counter(D)

if (D[0] != 0) or (C[0] != 1):
    print(0)
else:
    M = max(C.keys())
    ans = 1
    for i in range(M):
        ans = ans * pow(C[i], C[i+1], MOD) % MOD
    print(ans)
