class Counting():
    def __init__(self,n,mod):
        self.fac_arr = [1] * (n+1)
        self.r_s_fac_arr = [1] * (n+1)
        self.mod = mod
        for i in range(1,n+1):
            self.fac_arr[i] = (self.fac_arr[i-1]) * i % mod
            self.fac_arr[i] %= mod
        self.r_s_fac_arr[n] = pow(self.fac_arr[n],mod-2,mod)
        for i in range(n-1,-1,-1):
            self.r_s_fac_arr[i] = (self.r_s_fac_arr[i+1] % mod) * (i+1)
            self.r_s_fac_arr[i] %= mod
    def nckMod(self,n,k):
        mod = self.mod
        return self.fac_arr[n]  % mod *  self.r_s_fac_arr[k] % mod * self.r_s_fac_arr[n-k] % mod
    def npkMod(self,n,k):
        mod = self.mod
        return self.fac_arr[n]  % mod * self.r_s_fac_arr[n-k] % mod

n,k = map(int,input().split())
ans = 0
mod = 998244353
ct = Counting(n,mod)
for i in range(1,n):
#     print(i,n-1,ct.nckMod(n-1,i))
    ans += pow(i,k) * ct.nckMod(n-1,i)
    ans %= mod
print(ans)