# 二項係数

mod = 998244353
fac = [1, 1]
finv = [1, 1]
inv = [0, 1]


def init(n):
    for i in range(2, n + 1):
        fac.append(fac[-1] * i % mod)
        inv.append(-inv[mod % i] * (mod // i) % mod)
        finv.append(finv[-1] * inv[-1] % mod)


def com(n, k, mod):
    if n < 0 or k < 0 or n < k:
        return 0
    return fac[n] * (finv[k] * finv[n - k] % mod) % mod

init(10**5+10)
N = int(input())
M = int(input())
ans = pow(2,N,mod)
for i in range(M):
    ans = (ans-com(N,i,mod))%mod
print(ans)