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

#include<atcoder/modint>
using mint = atcoder::modint998244353;


const int B = 500;
mint fac[4<<17],ifac[4<<17];
mint comb(int n,int r){
    if(r>n) return 0;
    return fac[n] * ifac[r] * ifac[n-r];
}
int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    fac[0] = 1;
    for(int i = 1;i<4<<17;i++) fac[i] = fac[i-1] * i;
    for(int i = 0;i<4<<17;i++) ifac[i] = fac[i].inv();
    int t;
    cin>>t;
    vector<int> n(t),m(t);
    for(int i = 0;i<t;i++) cin>>n[i]>>m[i];
    vector<int> idx(t);
    for(int i = 0;i<t;i++) idx[i] = i;
    sort(idx.begin(),idx.end(),[&](int i,int j){
        if(n[i]/B!=n[j]/B) return n[i]/B < n[j]/B;
        if(n[i]/B%2) return m[i] < m[j];
        return m[i] > m[j];});

    int nn = 1,mm = 1;
    mint tmp = 1;
    vector<mint> ans(t);
    mint inv2 = (998244353+1)/2;
    for(int i = 0;i<t;i++){
        int ni = idx[i];
        while(m[ni]>mm){
            tmp += comb(2*mm,nn-1);
            mm++;
        }
        while(m[ni]<mm){
            tmp -= comb(2*(mm-1),nn-1);
            mm--;
        }
        while(n[ni]>nn){
            mint now = comb(2*mm,nn+1);
            tmp = (now-tmp) * inv2;
            nn++;
        }
        while(n[ni]<nn){
            mint now = comb(2*mm,nn);
            tmp = now - mint(2) * tmp;
            nn--;
        }
        ans[ni] = tmp;
    }
    for(int i = 0;i<t;i++) cout<<ans[i].val()<<endl;
}