#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define FORR2(x,y,arr) for(auto& [x,y]:arr)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
template<class T> bool chmax(T &a, const T &b) { if(a<b){a=b;return 1;}return 0;}
template<class T> bool chmin(T &a, const T &b) { if(a>b){a=b;return 1;}return 0;}
//-------------------------------------------------------

int T;
int N[202020],M[202020];
vector<pair<int,int>> ev[505];
ll ret[202020];
const ll mo=998244353;



ll comb(ll N_, ll C_) {
	const int NUM_=1430001;
	static ll fact[NUM_+1],factr[NUM_+1],inv[NUM_+1];
	if (fact[0]==0) {
		inv[1]=fact[0]=factr[0]=1;
		for (int i=2;i<=NUM_;++i) inv[i] = inv[mo % i] * (mo - mo / i) % mo;
		for (int i=1;i<=NUM_;++i) fact[i]=fact[i-1]*i%mo, factr[i]=factr[i-1]*inv[i]%mo;
	}
	if(C_<0 || C_>N_) return 0;
	return factr[C_]*fact[N_]%mo*factr[N_-C_]%mo;
}

ll F(ll n,ll m) {
	ll ret=0;
	for(int i=1;i<=m;i++) ret+=comb(2*(i-1),n-1);
	return ret%mo;
}

void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>T;
	FOR(i,T) {
		cin>>N[i]>>M[i];
		ev[M[i]/500].push_back({N[i],i});
	}
	FOR(i,500) {
		sort(ALL(ev[i]));
		int CN=-1,CM=-1;
		ll cur=0;
		FORR2(n,e,ev[i]) {
			if(CN==-1) {
				CN=N[e];
				CM=M[e];
				cur=F(CN,CM);
			}
			else {
				while(CN<N[e]) {
					cur=(comb(2*CM,CN+1)-cur+mo)*(mo+1)/2%mo;
					CN++;
				}
				while(CM<M[e]) {
					(cur+=comb(2*CM,CN-1))%=mo;
					CM++;
				}
				while(CM>M[e]) {
					CM--;
					(cur+=mo-comb(2*CM,CN-1))%=mo;
				}
			}
			ret[e]=cur;
		}
	}
	FOR(i,T) cout<<ret[i]<<endl;
	
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}