#include<bits/stdc++.h>
using namespace std;
#define N 200010
#define int long long
int c,T,n;
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struct node{
	int la,ra,b,k;
}a[N<<1];
inline void solve(){
//	cout<<"SOLVE:\n";
	cin>>n;
	int rmn=0,rmx=0,top=0;
	for(int i=1,l1,r1,l2,r2;i<=n;++i){
		cin>>l1>>r1>>l2>>r2;
		rmn+=l1;
		rmx+=r1;
		a[++top]={l1,r1,l2,1};
		a[++top]={l1,r1,r2+1,-1};
	}
	int lmn=0,lmx=0,cmx=0,ans=0;
	stable_sort(a+1,a+top+1,[](node a,node b){return a.b!=b.b?a.b<b.b:a.k<b.k;});
//	cout<<rmn<<' '<<rmx<<' '<<ans<<'\n';
	for(int i=1;i<top;++i){
		node &p=a[i];
		cmx+=p.ra*p.k;
		if(p.k<0){
			lmn+=p.la;
			lmx+=p.ra;
		}else{
			rmn-=p.la;
			rmx-=p.ra;
		}
//		cout<<"WFF:"<<i<<' '<<lmn<<' '<<lmx<<' '<<rmn<<' '<<rmx<<'\n';cout<<"Add:"<<i<<' '<<a[i+1].b-a[i].b<<'\n',
		if(!cmx)continue;
		if((lmn<=rmn&&rmn<=lmx)||(lmn<=rmx&&rmx<=lmx))ans+=a[i+1].b-a[i].b;
		else{
			int dlt=114514,tot=cmx;
			if(abs(rmn-lmx)>abs(rmx-lmn))dlt=rmx-lmn,tot+=rmx+lmn;
			else dlt=rmn-lmx,tot+=lmx+rmn;
			if(abs(dlt)<cmx){
//				cout<<"add:"<<i<<' '<<a[i+1].b-a[i].b<<'\n';
				ans+=a[i+1].b-a[i].b;
			}
			else if(abs(dlt)==cmx&&dlt>0&&(tot%2==0)){
				if(dlt>0){
//					cout<<"add:"<<i<<' '<<a[i+1].b-a[i].b<<'\n';
					ans+=a[i+1].b-a[i].b;
				}
			}
		}
	}
	cout<<ans<<'\n';
}
signed main(){
	freopen("lucky.in","r",stdin);
	freopen("lucky.out","w",stdout);
	ios::sync_with_stdio(0);
	cin.tie(0);cout.tie(0);
	cin>>c>>T;
	while(T--)solve();
	return 0;
}