mod = 998244353
eps = 10**-9


def main():
    import sys
    input = sys.stdin.readline

    # comb init
    nmax = 2 * 10 ** 5 + 10  # change here
    fac = [0] * nmax
    finv = [0] * nmax
    inv = [0] * nmax
    fac[0] = 1
    fac[1] = 1
    finv[0] = 1
    finv[1] = 1
    inv[1] = 1
    for i in range(2, nmax):
        fac[i] = fac[i - 1] * i % mod
        inv[i] = mod - inv[mod % i] * (mod // i) % mod
        finv[i] = finv[i - 1] * inv[i] % mod

    def comb(n, r):
        if n < r:
            return 0
        else:
            return (fac[n] * ((finv[r] * finv[n - r]) % mod)) % mod

    pow2 = [1] * 4001
    for i in range(4000):
        pow2[i+1] = (pow2[i] * 2)%mod

    x, y = map(int, input().split())
    assert x <= 4000 and y <= 4000
    if x > y:
        x, y = y, x

    ans = 0
    for i in range(x+1):
        for j in range(i+1):
            ans = (ans + ((comb(x + y - 2 * i + j, j) * comb(x + y - 2 * i, x - i))%mod * pow2[j])%mod)%mod
    print(ans)


if __name__ == '__main__':
    main()