N, K = map(int, input().split())
p = [0]*(K+1) # p[i]: second maxがi以下になる個数
MOD = 998244353

for i in range(1, K+1):
    p[i] = (pow(i, N, MOD)+N*(K-i)*pow(i, N-1, MOD))%MOD

ans = 0

for i in range(1, K+1):
    ans += (p[i]-p[i-1])*i%MOD
    ans %= MOD

print(ans)