#include<iostream>
#include<atcoder/modint>
using namespace std;
using mint=atcoder::modint998244353;
long N,X;
main()
{
	int T;cin>>T;
	for(;T--;)
	{
		cin>>N>>X;
		N++;
		mint ans=0;
		if(X%2==0)ans=N/2;
		else
		{
			ans=(N/(X+3))*((X+4)/2);
			N%=X+3;
			if(N==X+2)N--;
			if(N==X+1)N--,ans++;
			ans+=N/2;
		}
		cout<<ans.val()<<"\n";
	}
}