a,b=map(int,input().split()) MOD=998244353 def combo(n, k): def fact(n,k=0): a=1 for i in range(k+1,n+1): a=a * i % MOD return a k=min(k,n-k) a=fact(n, n-k) b=fact(k) return (a * pow(b, MOD-2, MOD)) % MOD print(combo(a+b-2,a-1))