N,K = map(int,input().split())
P = 998244353
C = N + 5
fact = [1] * C
for i in range(2,C):
    fact[i] = fact[i-1] * i % P
fact_inv = [1] * C
fact_inv[-1] = pow(fact[-1],P - 2,P)
for i in range(C - 2,0,-1):
    fact_inv[i] = fact_inv[i + 1] * (i + 1) % P

ans = 0
for k in range(1,N):
    tmp = fact[N - 1] * fact_inv[k] * fact_inv[N - 1 - k] % P
    ans += pow(k,K,P) * tmp % P
    ans %= P
print(ans)