#include<bits/stdc++.h>
using namespace std;
const long long MOD = 998244353;

long long modpow(long long a, long long b){
	long long ret = 1;
	a %= MOD;
	while(b){
		if(b & 1){
			ret *= a;
			ret %= MOD;
		}
		a *= a;
		a %= MOD;
		b >>= 1;
	}
	return ret;
}

void solve(){
	long long n, x, ans;
	cin >> n >> x;
	if(x & 1){
		ans = (n + 1) / 2;
	}
	else{
		long long  c = n / (2 * x + 2);
		n %= (2 * x + 2);
		/*
		0: lose
		1 ~ x : odd
		x + 1 ~ 2x: even
		2x + 1: win 
		*/
		ans = (x + 1) * c;
		if(n <= x){
			ans += (n + 1) / 2;
		}
		else{
			ans += (x + 1) / 2;
			n -= x;
			ans += n / 2;
			if(n == x + 1) ans++;

		}
	}
	cout << ans % MOD << "\n";
}

int main(){
	int t;
	t = 1;
	cin >> t;
	while(t--) solve();
}