import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################

n = ni()
m = ni()
mod = 998244353
ans = 0
z = 1
for i in range(m):
    ans += z
    ans %= mod
    z *= n - i
    z *= pow(i + 1, mod-2, mod)
    z %= mod

print((pow(2, n,mod)-ans)%mod)