import sys
#input = sys.stdin.readline
#input = sys.stdin.buffer.readline #文字列はダメ
#sys.setrecursionlimit(1000000)
#import bisect
#import itertools
#import random
#from heapq import heapify, heappop, heappush
#from collections import defaultdict 
#from collections import deque
#import copy
#import math
#from functools import lru_cache
#@lru_cache(maxsize=None)
#MOD = pow(10,9) + 7
MOD = 998244353
#dx = [1,0,-1,0]
#dy = [0,1,0,-1]
#dx8 = [1,1,0,-1,-1,-1,0,1]
#dy8 = [0,1,1,1,0,-1,-1,-1]

def cmb(n,k,MOD):
    top = 1
    bottom = 1
    for i in range(k):
        top *= (n-i)
        top %= MOD
        bottom *= (i+1)
        bottom %= MOD
    ret = top * pow(bottom,MOD-2,MOD) %MOD
    return ret


def main():
    N,M = map(int,input().split())
    #広義単調増加数列(=多重集合)を経路数に帰着する。
    n = 2*N+M
    k = 2*N+1
    print(N * cmb(n,k,MOD)%MOD)



if __name__ == '__main__':
    main()