def solve():
    N=int(input())
    M=int(input())

    Mod=998244353

    if N<M:
        return 0

    X=pow(2,N,Mod)
    Y=1
    for k in range(M):
        X-=Y
        Y=(Y*(N-k-1))%Mod
        Y=(Y*pow(k+1,Mod-2,Mod))%Mod
    return X%Mod

#==================================================
print(solve())