MOD = 998244353
a,b = map(int,input().split())
A = [1]*(a+b+1)
for i in range(2,a+b+1):
    A[i] = (A[i-1]*i)%MOD
B = [1]*(a+b+1)
B[a+b] = pow(A[a+b],MOD-2,MOD)
for i in range(a+b-1,0,-1):
    B[i] = (B[i+1]*(i+1))%MOD
print((A[a+b-2]*B[a-1]*B[b-1])%MOD)