/* Things to notice: 1. do not calculate useless values 2. do not use similar names Things to check: 1. submit the correct file 2. time (it is log^2 or log) 3. memory 4. prove your naive thoughts 5. long long 6. corner case like n=0,1,inf or n=m 7. check if there is a mistake in the ds or other tools you use 8. fileio in some oi-contest 9. module on time 10. the number of a same divisor in a math problem 11. multi-information and queries for dp and ds problems */ #include using namespace std; #define int long long #define fi first #define se second #define pii pair #define mp make_pair #define pb push_back const int mod=998244353; const int inf=0x3f3f3f3f; const int INF=1e18; void solve() { int n,m; cin>>n>>m; int ans=n*m%mod*((n*m-1)%mod)%mod; if(m%2==0) { ans=(ans-n*(2*m-2)%mod+mod)%mod; int x=m/2-1; if(x) x--,x=x*(x+1),x%=mod,ans=(ans-n*x%mod+mod)%mod; } else { ans=(ans-n*(m-1)%mod+mod)%mod; int x=m/2; if(x) x--,x=x*(x+1),x%=mod,ans=(ans-n*x%mod+mod)%mod; } swap(n,m); if(m%2==0) { ans=(ans-n*(2*m-2)%mod+mod)%mod; int x=m/2-1; if(x) x--,x=x*(x+1),x%=mod,ans=(ans-n*x%mod+mod)%mod; } else { ans=(ans-n*(m-1)%mod+mod)%mod; int x=m/2; if(x) x--,x=x*(x+1),x%=mod,ans=(ans-n*x%mod+mod)%mod; } int lim1=(n+1)/2,lim2=(m+1)/2; n-=lim1-1,m-=lim2-1; n--,m--; n=n*(n+1)/2,n%=mod; m=m*(m+1)/2,m%=mod; ans=(ans-4LL*n*m%mod+mod)%mod; cout<>_; while(_--) solve(); return 0; }