/// Gheorghies Alexandru
#include<bits/stdc++.h>

using namespace std;
typedef long long ll;
void tc(){
    ll n,m;
    cin>>n>>m;
    cout<<(n*m*2+2)/3<<'\n';
}
int main()
{
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
    ll t; cin>>t; while(t--)
        tc();
    return 0;
}