import sys
from collections import deque, Counter
sys.setrecursionlimit(5 * 10 ** 5)
from pypyjit import set_param
set_param('max_unroll_recursion=-1')
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
inf = 2 ** 63 - 1
mod = 998244353

n = ii()

m = ii()

if n < m:
    print(0)
    exit()
ans = pow(2, n, mod)

C = 1
for i in range(m):
    ans -= C
    ans %= mod
    C *= (n - i)
    C %= mod
    C *= pow(i + 1, mod - 2, mod)
    C %= mod
print(ans)