#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=1e5+10;
ll a[N],b[N];
int main(){
    int t;cin>>t;
    while(t--){
        ll n;cin>>n;
        for(int i=1;i<=n;i++){cin>>a[i];cin>>b[i];}
        if(n==1){cout<<1<<endl;continue;}
        ll ls=1e9,rs=0,lm=1e9,rm=0;
        for(int i=1;i<=n;i++){
            lm=min(lm,a[i]);
            rm=max(rm,b[i]);
        }
        for(int i=1;i<=n;i++){
            if(a[i]!=lm)ls=min(ls,a[i]);
            if(b[i]!=rm)rs=max(rs,b[i]);
        }
        if(ls==1e9)ls=lm;
        if(rs==0)rs=rm;
        //cout<<ls<<" "<<rs<<endl;
        //cout<<lm<<" "<<rm<<endl;

        ll ans=0;
        if(rs<ls){
            ans=(rm-ls+1)*(rs-lm+1);
            cout<<ans<<endl;
            continue;
        }
        ans=(rm-lm+1)*(rm-lm)/2;
        if(ls!=lm){
            ans-=(ls-lm)*(ls-lm-1)/2;
        }
        if(rs!=rm){
            ans-=(rm-rs)*(rm-rs-1)/2;
        }
        cout<<ans<<endl;
    }
}