from collections import defaultdict
from itertools import combinations_with_replacement
import sys
input = sys.stdin.readline
def iinput(): return int(input())
def sinput(): return input().rstrip()
def i0input(): return int(input()) - 1
def linput(): return list(input().split())
def liinput(): return list(map(int, input().split()))
def miinput(): return map(int, input().split())
def li0input(): return list(map(lambda x: int(x) - 1, input().split()))
def mi0input(): return map(lambda x: int(x) - 1, input().split())
INF = 10**20
MOD = 998244353

def modinv(a):
    b = MOD
    u, v = 1, 0
    while b > 0:
        t = a // b
        a -= t * b
        a, b = b, a
        u -= t * v
        u, v = v, u
    return u % MOD
 
def combi(n, k):
    k = max(k, n-k)
    ans = 1
    for i in range(n, k, -1):
        ans *= i
        ans %= MOD
    tmp = 1
    for i in range(2, n-k+1):
        tmp *= i
        tmp %= MOD
    return ans * modinv(tmp) % MOD

def solve_naive(N, M):
    ans = 0
    for res in combinations_with_replacement(range(M+1), 2*N):
        tmp = 0
        for i in range(N):
            tmp += abs(res[2*i] - res[2*i+1])
        ans += tmp
    return ans

def solve_naive2(N, M):
    ans = 0
    for k in range(M+1):
        ans += k * combi(k+N-1, k) * combi(M+N-k, M-k)
    return ans

N, M = liinput()
print(combi(2*N+M, 2*N+1) * N % MOD)