#include<cstdio>
#include<vector>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<map>
#include<string>
const int N = 600300;
const int mod = 998244353;
using ll = long long;
using namespace std;
using pii = pair<int,int>;
const int INF = 0x3f3f3f3f;
int read(){
    int x=0,flag=1;char c;
    while((c=getchar())<'0' || c>'9') if(c=='-') flag=-1;
    while(c>='0' && c<='9') x=(x<<3)+(x<<1)+(c^48),c=getchar();
    return x*flag;
}
int l[N],r[N];
int main()
{
    int T=read();
    while(T--)
    {
        int n=read();
        for (int i=1;i<=n;++i) l[i]=read(),r[i]=read();
        if (n==1) printf("1\n");
        else if (n==2)
        {
            ll ans=0;
            if (l[1]>l[2]) swap(l[1],l[2]), swap(r[1],r[2]);
            if (r[1]<l[2]) ans = 1ll*(r[1]-l[1]+1)*(r[2]-l[2]+1);
            else if (r[1]<=r[2])
            {// l1 l2 r1 r2
                int L=l[1],R=r[2],SL=l[2],SR=r[1];
                ans = (SR-SL+1ll)*(SR-SL)/2 + 1ll*(SR-SL+1)*(SL-L+R-SR);
                ans += 1ll*(SL-L)*(R-SR);
            }else
            {// l1 l2 r2 r1
                int L=l[1],R=r[1],SL=l[2],SR=r[2];
                ans = (SR-SL+1ll)*(SR-SL)/2 + 1ll*(SR-SL+1)*(SL-L+R-SR);
            }
            printf("%lld\n",ans);
        }else
        {
            ll ans=0;
            int L=INF,L1=0,R0=INF,R=0,SL=INF,SR=0;
            int Lidx=0,Ridx=0;
            for (int i=1;i<=n;++i)
            {
                if (l[i]<L) 
                {
                    if (Lidx!=Ridx)
                        SL=min(L,SL), SR=max(SR, L1);
                    L=l[i];L1=r[i];
                    Lidx=i;
                    if (r[i]>R)
                    {
                        SR=max(R, SR), SL=min(SL, R0);
                        R=r[i]; R0=l[i];
                        Ridx=i;
                    }
                }
                else if (r[i]>R||r[i]==R&&Ridx==Lidx)
                {
                    if (Ridx!=Lidx)
                        SR=max(R, SR), SL=min(SL, R0);
                    R=r[i]; R0=l[i];
                    Ridx=i;
                } 
                else {
                    if (r[i]>SR) SR=r[i];
                    if (l[i]<SL) SL=l[i];
                }
            }
            //printf("L=%d R=%d SL=%d SR=%d\n",L,R,SL,SR);
            if (Ridx!=Lidx)
            {
                // L , SL , SR, R
                ans = (SR-SL+1ll)*(SR-SL)/2 + 1ll*(SR-SL+1)*(SL-L+R-SR);
                // [L, SR] [R0, R] 
                int TL=max(L1,SR), TR=min(SL,R0);
                // [L, TL] [TR, R]
                ans += 1ll*(min(TL+1, SL)-L) * (R-max(SR, TR-1));
            }else
            {
                ans = (SR-SL+1ll)*(SR-SL)/2 + 1ll*(SR-SL+1)*(SL-L+R-SR);
            }
            printf("%lld\n",ans);
        }
    }
}