import sys
INF = float('inf')
#10**20,2**63,float('inf')
MOD = 10**9 + 7
MOD2 = 998244353
from collections import defaultdict
def solve():
    def II(): return int(sys.stdin.readline())
    def LI(): return list(map(int, sys.stdin.readline().split()))
    def LC(): return list(input())
    def IC(): return [int(c) for c in input()]
    def MI(): return map(int, sys.stdin.readline().split())
    N = II()
    M = II()
    def modinv(x):
        return pow(x, MOD2 - 2, MOD2)
    All = pow(2,N,MOD2)
    Dec = 0
    for m in range(M):
        if(m==0):Dec+=1
        elif(m==1):
            Dec+=N%MOD2
            now = N
        else:
            now*=(N-(m-1))*modinv(m)
            now%=MOD2
            Dec+=now
            Dec%=MOD2
    print((All-Dec)%MOD2)
    return
solve()