#include<stdio.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#include<atcoder/modint>
typedef atcoder::modint998244353 mint;
using namespace std;
using ll=long long;
const int mod=998244353;
const int rev=748683265;


int main(){
    int N,K;
    scanf("%d%d",&N,&K);
    printf("%d\n",((3*N+2*K+((mint)(N-2)).pow(K)*((mint)(N)).pow(mod-K))*rev).val());
}