mod=998244353

# FFT
# mod=998244353　における、NTTによる高速フーリエ変換、畳み込み
# 他の提出を参考にしており、あまり理解できていません……
mod=998244353
 
Weight=[1, 998244352, 911660635, 372528824, 929031873, 452798380, 922799308, 781712469, 476477967, 166035806, 258648936, 584193783, 63912897, 350007156, 666702199, 968855178, 629671588, 24514907, 996173970, 363395222, 565042129, 733596141, 267099868, 15311432, 0]
Weight_inv=[1, 998244352, 86583718, 509520358, 337190230, 87557064, 609441965, 135236158, 304459705, 685443576, 381598368, 335559352, 129292727, 358024708, 814576206, 708402881, 283043518, 3707709, 121392023, 704923114, 950391366, 428961804, 382752275, 469870224, 0]
 
def fft(A,n,h,inverse=0):
 
    if inverse==0:
    
        for i in range(h):
            m=1<<(h-i-1)
            for j in range(1<<i):
                w=1     
                ij=j*m*2
                
                wk=Weight[h-i]
                    
                for k in range(m):
                    A[ij+k],A[ij+k+m]=(A[ij+k]+A[ij+k+m])%mod,(A[ij+k]-A[ij+k+m])*w%mod
                    w=w*wk%mod
    else:
        for i in range(h):
            m=1<<i
            for j in range(1<<(h-i-1)):
                w=1     
                ij=j*m*2
                
                wk=Weight_inv[i+1]
                    
                for k in range(m):
                    A[ij+k],A[ij+k+m]=(A[ij+k]+A[ij+k+m]*w)%mod,(A[ij+k]-A[ij+k+m]*w)%mod
                    w=w*wk%mod
        
 
    if inverse==1:
        INV_n=pow(n,mod-2,mod)
        for i in range(n):
            A[i]=A[i]*INV_n%mod
 
    return A
 
def convolution(A,B):
    
    FFTLEN=len(A)+len(B)-1
    h=FFTLEN.bit_length()
    LEN=2**h
 
    A+=[0]*(LEN-len(A)) # A,Bのサイズを2ベキに揃える
    B+=[0]*(LEN-len(B))
 
    A_FFT=fft(A,LEN,h)
    B_FFT=fft(B,LEN,h)
 
    for i in range(len(A)):
        A[i]=A[i]*B[i]%mod
 
    A=fft(A,LEN,h,1)
 
    return A[:FFTLEN]

FACT=[1]
for i in range(1,6*10**5+1):
    FACT.append(FACT[-1]*i%mod)

FACT_INV=[pow(FACT[-1],mod-2,mod)]
for i in range(6*10**5,0,-1):
    FACT_INV.append(FACT_INV[-1]*i%mod)

FACT_INV.reverse()

def Combi(a,b):
    if 0<=b<=a:
        return FACT[a]*FACT_INV[b]%mod*FACT_INV[a-b]%mod
    else:
        return 0

def calc(N):
    LIST=[0]*(N+1)

    one=N
    two=0

    while one>=0 and two>=0:
        LIST[one+two]=Combi(one+two,one)
        two+=1
        one-=2

    return LIST

H,W=map(int,input().split())

A=calc(H)
B=calc(W)

for i in range(len(A)):
    A[i]*=FACT_INV[i]
    A[i]%=mod

for i in range(len(B)):
    B[i]*=FACT_INV[i]
    B[i]%=mod

X=convolution(A,B)

ANS=0

for i in range(len(X)):
    ANS+=X[i]*FACT[i]
    ANS%=mod

print(ANS)