import sys sys.setrecursionlimit(200005) # sys.set_int_max_str_digits(200005) int1 = lambda x: int(x)-1 pDB = lambda *x: print(*x, end="\n", file=sys.stderr) p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr) def II(): return int(sys.stdin.readline()) def LI(): return list(map(int, sys.stdin.readline().split())) def LLI(rows_number): return [LI() for _ in range(rows_number)] def LI1(): return list(map(int1, sys.stdin.readline().split())) def LLI1(rows_number): return [LI1() for _ in range(rows_number)] def SI(): return sys.stdin.readline().rstrip() dij = [(0, 1), (-1, 0), (0, -1), (1, 0)] # dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)] inf = (1 << 63)-1 # md = 10**9+7 md = 998244353 IMAG = 911660635 IIMAG = 86583718 rate2 = ( 0, 911660635, 509520358, 369330050, 332049552, 983190778, 123842337, 238493703, 975955924, 603855026, 856644456, 131300601, 842657263, 730768835, 942482514, 806263778, 151565301, 510815449, 503497456, 743006876, 741047443, 56250497, 867605899, 0) irate2 = (0, 86583718, 372528824, 373294451, 645684063, 112220581, 692852209, 155456985, 797128860, 90816748, 860285882, 927414960, 354738543, 109331171, 293255632, 535113200, 308540755, 121186627, 608385704, 438932459, 359477183, 824071951, 103369235, 0) rate3 = ( 0, 372528824, 337190230, 454590761, 816400692, 578227951, 180142363, 83780245, 6597683, 70046822, 623238099, 183021267, 402682409, 631680428, 344509872, 689220186, 365017329, 774342554, 729444058, 102986190, 128751033, 395565204, 0) irate3 = (0, 509520358, 929031873, 170256584, 839780419, 282974284, 395914482, 444904435, 72135471, 638914820, 66769500, 771127074, 985925487, 262319669, 262341272, 625870173, 768022760, 859816005, 914661783, 430819711, 272774365, 530924681, 0) def butterfly(a): n = len(a) h = (n-1).bit_length() le = 0 while le < h: if h-le == 1: p = 1 << (h-le-1) rot = 1 for s in range(1 << le): offset = s << (h-le) for i in range(p): l = a[i+offset] r = a[i+offset+p]*rot a[i+offset] = (l+r)%md a[i+offset+p] = (l-r)%md rot *= rate2[(~s & -~s).bit_length()] rot %= md le += 1 else: p = 1 << (h-le-2) rot = 1 for s in range(1 << le): rot2 = rot*rot%md rot3 = rot2*rot%md offset = s << (h-le) for i in range(p): a0 = a[i+offset] a1 = a[i+offset+p]*rot a2 = a[i+offset+p*2]*rot2 a3 = a[i+offset+p*3]*rot3 a1na3imag = (a1-a3)%md*IMAG a[i+offset] = (a0+a2+a1+a3)%md a[i+offset+p] = (a0+a2-a1-a3)%md a[i+offset+p*2] = (a0-a2+a1na3imag)%md a[i+offset+p*3] = (a0-a2-a1na3imag)%md rot *= rate3[(~s & -~s).bit_length()] rot %= md le += 2 def butterfly_inv(a): n = len(a) h = (n-1).bit_length() le = h while le: if le == 1: p = 1 << (h-le) irot = 1 for s in range(1 << (le-1)): offset = s << (h-le+1) for i in range(p): l = a[i+offset] r = a[i+offset+p] a[i+offset] = (l+r)%md a[i+offset+p] = (l-r)*irot%md irot *= irate2[(~s & -~s).bit_length()] irot %= md le -= 1 else: p = 1 << (h-le) irot = 1 for s in range(1 << (le-2)): irot2 = irot*irot%md irot3 = irot2*irot%md offset = s << (h-le+2) for i in range(p): a0 = a[i+offset] a1 = a[i+offset+p] a2 = a[i+offset+p*2] a3 = a[i+offset+p*3] a2na3iimag = (a2-a3)*IIMAG%md a[i+offset] = (a0+a1+a2+a3)%md a[i+offset+p] = (a0-a1+a2na3iimag)*irot%md a[i+offset+p*2] = (a0+a1-a2-a3)*irot2%md a[i+offset+p*3] = (a0-a1-a2na3iimag)*irot3%md irot *= irate3[(~s & -~s).bit_length()] irot %= md le -= 2 def multiply(s, t): n = len(s) m = len(t) if min(n, m) <= 60: a = [0]*(n+m-1) for i in range(n): if i%8 == 0: for j in range(m): a[i+j] += s[i]*t[j] a[i+j] %= md else: for j in range(m): a[i+j] += s[i]*t[j] return [x%md for x in a] a = s.copy() b = t.copy() z = 1 << (n+m-2).bit_length() a += [0]*(z-n) b += [0]*(z-m) butterfly(a) butterfly(b) for i in range(z): a[i] *= b[i] a[i] %= md butterfly_inv(a) a = a[:n+m-1] iz = pow(z, md-2, md) return [v*iz%md for v in a] def nPr(com_n, com_r): if com_r < 0: return 0 if com_n < com_r: return 0 return fac[com_n]*ifac[com_n-com_r]%md def nCr(com_n, com_r): if com_r < 0: return 0 if com_n < com_r: return 0 return fac[com_n]*ifac[com_r]%md*ifac[com_n-com_r]%md n_max = 400005 fac = [1] for i in range(1, n_max+1): fac.append(fac[-1]*i%md) ifac = [1]*(n_max+1) ifac[n_max] = pow(fac[n_max], md-2, md) for i in range(n_max-1, 1, -1): ifac[i] = ifac[i+1]*(i+1)%md h, w = LI() def toxx(h): xx = [0]*(h+1) for i in range((h+1)//2, h+1): xx[i] = nCr(i, h-i)*ifac[i]%md return xx xx = toxx(h) yy = toxx(w) zz=multiply(xx,yy) ans=0 for i in range(len(zz)): ans+=zz[i]*fac[i]%md ans%=md print(ans)