import sys input = sys.stdin.readline from collections import * MOD = 998244353 N = int(input()) M = int(input()) if N<M: print(0) exit() ans = pow(2, N, MOD) sub = 1 for i in range(M): ans -= sub ans %= MOD sub *= N-i sub %= MOD sub *= pow(i+1, MOD-2, MOD) sub %= MOD print(ans)