import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.complex, std.container, std.math, 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; }
real readReal() { return readToken.to!real; }

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)); }


struct ModInt(long M) {
  long x;
  this(in ModInt a) { x = a.x; }
  this(in long a) { x = a % M; if (x < 0) x += M; }
  ModInt opUnary(string op)() if (op == "-") { return ModInt(-x); }
  ref ModInt opOpAssign(string op)(in ModInt a) {
    static if (op == "+") { x += a.x; if (x >= M) x -= M; }
    else static if (op == "-") { x -= a.x; if (x < 0) x += M; }
    else static if (op == "*") { x *= a.x; x %= M; }
    else static assert(false);
    return this;
  }
  ModInt opOpAssign(string op)(in long a) { return mixin("this " ~ op ~ "= ModInt(a)"); }
  ModInt opBinary(string op, T)(in T a) const { return mixin("ModInt(this) " ~ op ~ "= a"); }
  ModInt opBinaryRight(string op)(in long a) const { return mixin("ModInt(a) " ~ op ~ "= this"); }
  string toString() const { return x.to!string; }
}

enum long MO = 998244353;
alias Mint = ModInt!MO;
enum LIM = 3 * 10^^6;

long[] inv, fac, invFac;
void prepare() {
  inv = new long[LIM];
  fac = new long[LIM];
  invFac = new long[LIM];
  inv[1] = 1;
  foreach (i; 2 .. LIM) {
    inv[i] = MO - ((MO / i) * inv[cast(size_t)(MO % i)]) % MO;
  }
  fac[0] = invFac[0] = 1;
  foreach (i; 1 .. LIM) {
    fac[i] = (fac[i - 1] * i) % MO;
    invFac[i] = (invFac[i - 1] * inv[i]) % MO;
  }
}
long binom(long n, long k) {
  if (0 <= k && k <= n) {
    assert(n < LIM);
    return fac[cast(size_t)(n)] * invFac[cast(size_t)(k)] % MO * invFac[cast(size_t)(n - k)] % MO;
  } else {
    return 0;
  }
}


void main() {
  /*
  foreach (m; 1 .. 10 + 1) foreach (n; 1 .. 10 + 1) if (m * n <= 16) {
    int[][][] as;
    int cnt;
    foreach (p; 0 .. (n + 1)^^m) foreach (q; 0 .. (m + 1)^^n) {
      auto a = new int[][](m, n);
      bool ok = true;
      foreach (x; 0 .. m) foreach (y; 0 .. n) {
        const k = p / (n + 1)^^x % (n + 1);
        const l = q / (m + 1)^^y % (m + 1);
        ok = ok && !(k == y && l == x + 1);
        if (y < k) ++a[x][y];
        if (x < l) ++a[x][y];
      }
      as ~= a;
      if (ok) {
        ++cnt;
      }
    }
    as = as.sort.uniq.array;
    writeln(m, " ", n, ": ", as.length, " ", cnt);
    stdout.flush;
    if (m == 2 && n == 2) {
      foreach (a; as) {
        writeln(a);
      }
    }
  }
  return;
  */
  
  prepare();
  
  try {
    for (; ; ) {
      const M = readInt();
      const N = readInt();
      
      auto pwN1 = new Mint[M + 1];
      auto pwM1 = new Mint[N + 1];
      pwN1[0] = Mint(1);
      foreach (i; 1 .. M + 1) {
        pwN1[i] = pwN1[i - 1] * (N + 1);
      }
      pwM1[0] = Mint(1);
      foreach (i; 1 .. N + 1) {
        pwM1[i] = pwM1[i - 1] * (M + 1);
      }
      
      Mint ans;
      foreach (l; 0 .. min(M, N) + 1) {
        Mint tmp = (l % 2 != 0) ? -1 : +1;
        tmp *= binom(M, l);
        tmp *= binom(N, l);
        tmp *= fac[l];
        tmp *= pwN1[M - l];
        tmp *= pwM1[N - l];
        ans += tmp;
      }
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}
