import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }

string COLOR(string s = "") { return "\x1b[" ~ s ~ "m"; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


/*
  state -(M-1), ..., M
  -(M-1) <= u <= 0  ~~>  u+1, ..., u+M
  1 <= u <= M       ~~>  u-M, ..., u-1
  identify states by mod (M+1)
  ~~> typical counting: seqs in [1, M]^N s.t. (M+1) | sum
*/

BigInt mod(BigInt a, BigInt m) {
  return ((a %= m) < 0) ? (a + m) : a;
}
BigInt power(BigInt a, long e, BigInt m) {
  BigInt b = a, c = 1;
  for (; ; b = mod(b * b, m)) {
    if (e & 1) c = mod(c * b, m);
    if (!(e >>= 1)) return c;
  }
}

enum MO = 998244353L;

void main() {
  try {
    for (; ; ) {
      const N = readLong;
      const M = readLong;
      
      const mo = BigInt(MO) * BigInt(M+1);
      BigInt t = mod(power(BigInt(M), N, mo) + M * (N&1?-1:+1), mo);
      assert(t % (M+1) == 0);
      t /= (M+1);
      writeln(t);
    }
  } catch (EOFException e) {
  }
}