MOD = 998244353

n, m = map(int, input().split())

dp = [[0] * (m + 1) for _ in range(n + 1)]
dp[0][0] = 1
tot = [0] * (n + 1)
tot[0] = 1
powm = [1]
for _ in range(n):
    powm.append(powm[-1] * m % MOD)

ans = 0
for i in range(1, n + 1):
    ans += tot[i - 1] * powm[n - i]
    ans %= MOD
    for j in range(2, m + 1):
        dp[i][j] = tot[i - 1]
        if i >= j:
            dp[i][j] -= tot[i - j] - dp[i - j][j]
            ans += (tot[i - j] - dp[i - j][j]) * powm[n - i]
            ans %= MOD
        dp[i][j] %= MOD
        tot[i] += dp[i][j]
        tot[i] %= MOD

print(ans)