import sys,random,bisect
from collections import deque,defaultdict
from heapq import heapify,heappop,heappush
from itertools import permutations
from math import log,gcd

input = lambda :sys.stdin.readline().rstrip()
mi = lambda :map(int,input().split())
li = lambda :list(mi())

mod = 998244353

N,M = mi()

res = N
for i in range(2*N+1):
    res *= (M+2*N-i) % mod
    res %= mod
    res *= pow(i+1,mod-2,mod)
    res %= mod

print(res)