import sys input = lambda : sys.stdin.readline().rstrip() write = lambda x: sys.stdout.write(x+"\n") debug = lambda x: sys.stderr.write(x+"\n") writef = lambda x: print("{:.12f}".format(x)) n,m = list(map(int, input().split())) a = list(map(int, input().split())) M = 998244353 ### 素数の逆元とCombination N = n+m+10 # 必要なテーブルサイズ g1 = [0] * (N+1) # 元テーブル g2 = [0] * (N+1) #逆元テーブル inverse = [0] * (N+1) #逆元テーブル計算用テーブル g1[0] = g1[1] = g2[0] = g2[1] = 1 inverse[0], inverse[1] = [0, 1] for i in range( 2, N + 1 ): g1[i] = ( g1[i-1] * i ) % M inverse[i] = ( -inverse[M % i] * (M//i) ) % M # ai+b==0 mod M <=> i==-b*a^(-1) <=> i^(-1)==-b^(-1)*aより g2[i] = (g2[i-1] * inverse[i]) % M def cmb(n, r, M=M): if ( r<0 or r>n ): return 0 r = min(r, n-r) return ((g1[n] * g2[r] % M) * g2[n-r]) % M def perm(n, r, M=M): if (r<0 or r>n): return 0 return (g1[n] * g2[n-r]) % M dp = [0]*(m+1) dp[0] = 1 mask = (1<>k&1: ans += cmb(m-k, l-k) ans %= M break print(ans%M)