#include<bits/stdc++.h>
#define For(a,b,c) for(int a=b;a<=c;++a)
#define Dor(a,b,c) for(int a=b;a>=c;--a)
#define CC(_...) fprintf(stderr,_)
using namespace std;
typedef long long LL;
const int N=200007;
int n,e,ml,sr,L[N],R[N],E[N],D[N],W[N],F[N];
void magic() {
	scanf("%d",&n);
	e=sr=0;
	For(i,1,n) {
		scanf("%d%d",&L[i],&R[i]);
		E[++e]=R[i],E[++e]=L[i]-1;
	}
	if(n==1) {
		puts("1");
		return;
	}
	sort(E+1,E+1+e),e=unique(E+1,E+1+e)-E-1;
	For(i,1,e) D[i]=W[i]=F[i]=0;
	F[e]=E[e];
	For(i,1,n) {
		int l=lower_bound(E+1,E+1+e,L[i]-1)-E;
		int r=lower_bound(E+1,E+1+e,R[i])-E;
		if(r==E[e]) ml=L[i];
		else sr=max(sr,R[i]);
		D[l+1]++,D[r+1]--,W[r]++;
		F[l]=L[i]-1;
	}
	if(W[e]>1) sr=E[e];
	Dor(i,e,1) if(!F[i]) F[i]=F[i+1];
	LL ans=0;
	int p=0;
	For(i,2,e) {
		D[i]+=D[i-1];
		if(!D[i]) {
			if(p>=2&&p<=n-2) {
				ans+=1LL*(E[i]-E[i-1])*(E[i]-E[i-1]-1)/2;
				ans+=1LL*(E[i]-E[i-1])*(E[e]-E[i]);
			}
			else if(p==1&&n>=3) {
				int c=0,s=0,l=E[e];
				For(j,1,n) {
					if(L[j]>E[i]) {
						l=min(l,L[j]);
						++c;
						s+=R[j]-L[j];
					}
				}
				if(c>=3) ans+=1LL*(E[i]-E[i-1])*(E[e]-l);
				else ans+=1LL*(E[i]-E[i-1])*s;
			}
		}
		else {
			if(D[i]>1||p&&i!=e) {
				ans+=1LL*(E[i]-E[i-1])*(E[i]-E[i-1]-1)/2;
				ans+=1LL*(E[i]-E[i-1])*(E[e]-E[i]);
			}
			else {
				int r=E[e];
				if(D[i]==1&&ml<=E[i]) {
					r=sr;
				}
				ans+=1LL*(E[i]-E[i-1])*max(0,sr-F[i]);
			}
		}
		p+=W[i];
	}
	printf("%lld\n",ans);
}
int main() {
	int T; scanf("%d",&T);
	while(T--) magic();
	return 0;
}