def nCr(n,r):
    a=b=1
    while r:
        a*=n; a%=Mod
        b*=r; b%=Mod

        n-=1; r-=1
    return (a*pow(b,Mod-2,Mod))%Mod

N,M=map(int,input().split())
Mod=998244353

print(N*nCr(2*N+M,2*N+1)%Mod)