N, K = map(int, input().split())
dp = [[0 for _ in range(N + 1)] for _ in range(K + 1)]
dp[0][0] = 1

mod = 998244353

for i in range(K):
    for j in range(N + 1):
        if j > 0:
            dp[i + 1][j - 1] = (dp[i + 1][j - 1] + dp[i][j] * j) % mod
        if j < N:
            dp[i + 1][j + 1] = (dp[i + 1][j + 1] + dp[i][j] * (N - j)) % mod

div = pow(pow(N, K, mod), mod - 2, mod)
ans = 0
for i in range(N + 1):
    ans = (ans + ((K - i) // 2 + N) * dp[K][i]) % mod
print((ans * div) % mod)