#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
	int T;
	cin>>T;
	int mod = 998244353;
	while(T--){
		int N,M;
		cin>>N>>M;
		int a = 1, b = 0, c = 0;
		for(int i=0;i<M;i++){
			int aa = a+b+c;
			int bb = a*N+b*(N-1)+c*(N-2);
			int cc = a*N*(N-3)/2+b*(N-2)*(N-3)/2+c*(N-3+(N-4)*(N-5)/2);
			a = max(0ll,aa), b = max(0ll,bb), c = max(0ll,cc);
			a %= mod;
			b %= mod;
			c %= mod;
			//cout<<a<<' '<<b<<' '<<c<<endl;
		}
		cout<<(a+b+c)%mod<<endl;
	}
}