MOD = 998244353i64 def inv(v) pow(v, MOD - 2) end def pow(v, p) ret = 1i64 while p > 0 if (p & 1i64) != 0 ret *= v ret %= MOD end v *= v v %= MOD p >>= 1 end ret end n, k = read_line.split.map(&.to_i) dp = Array.new(k + 1) { Array.new(n + 1, 0i64) } dp[0][0] = 1 1.upto(k) do |i| 0.upto(n) do |j| if j < n dp[i][j + 1] += dp[i - 1][j] * (n - j) dp[i][j + 1] %= MOD end if j > 0 dp[i][j - 1] += dp[i - 1][j] * j dp[i][j - 1] %= MOD end end end ans = 0i64 0.upto({n, k}.min) do |i| c = (k - i) // 2 ans += dp[-1][i] * (n + c) ans %= MOD end puts ans * inv(pow(n.to_i64, k)) % MOD