//GZ-023 易主一 北京师范大学贵阳附属中学
//T1 lucky
//1s 512MB
//400T


#include<bits/stdc++.h>

using namespace std;


using i128=__int128;
using u128=unsigned __int128;
using i64=long long;
using u64=unsigned long long;
using i32=int;
using u32=unsigned int;
using i16=short;
using u16=unsigned short;
using i8=char;
using u8=unsigned char;
using pii=pair<int,int>;

template<typename T>
inline void read(T& v){
    v=0;
    char c=getchar();
    while(c<'0'||c>'9'){
        c=getchar();
    }
    while(c>='0'&&c<='9'){
        v*=10;
        v+=c-'0';
        c=getchar();
    }
}

template<typename T>
inline void write_(T v){
    if(v==0){
        return;
    }
    write_(v/10);
    putchar((v%10)+'0');
}

template<typename T>
inline void write(T v){
    if(v==0){
        putchar('0');
        return;
    }
    write_(v);
}

template<typename T>
inline void writeln(T v){
    write(v);
    putchar('\n');
}


//4MB
int al[200010][2];//1e9
int bl[200010][2];//1e9

struct Node;

Node* alloc();

struct Node{
    Node* child;
    i64 val[2];//lmax+mid-rmin,rmax+mid-lmin

    Node(){

    };

    inline void clear(){
        child=NULL;
        val[0]=0;
        val[1]=0;
    }

    inline void push_down(){
        if(child==NULL){
            child=alloc();
            alloc();
        }
        for(int i=0;i<2;i++){
            for(int j=0;j<2;j++){
                child[i].val[j]+=val[j];
            }
        }
        for(int j=0;j<2;j++){
            val[j]=0;
        }
    }
};
//400MB
Node pool[17476266];
int pool_top=0;

inline Node* alloc(){
    pool[pool_top].clear();
    return &pool[pool_top++];
}

Node* root;
const int E9=1000000000;
const int E91=E9+1;

void range_add_p2(Node* cur,int l,int r,int ql,int qr,int val1,int val2){
    if(l>=ql&&r<=qr){
        cur->val[0]+=val1;
        cur->val[1]+=val2;
        return;
    }
    if(l>=qr||r<=ql){
        return;
    }
    cur->push_down();
    int mid=(l+r)>>1;
    range_add_p2(cur->child,l,mid,ql,qr,val1,val2);
    range_add_p2(cur->child+1,mid,r,ql,qr,val1,val2);
}

inline void range_add_p2(int ql,int qr,int val1,int val2){
    return range_add_p2(root,0,E91,ql,qr,val1,val2);
}


i64* get_val(Node* cur,int l,int r,int pos){
    if(cur->child==NULL){
        return cur->val;
    }
    cur->push_down();
    int mid=(l+r)>>1;
    if(pos>=mid){
        return get_val(cur->child+1,mid,r,pos);
    }else{
        return get_val(cur->child,l,mid,pos);
    }
}

inline i64* get_val(int pos){
    return get_val(root,0,E91,pos);
}

inline bool checkl(int p){
    i64* v=get_val(p);
    return v[0]>=0;
}

inline bool checkr(int p){
    i64* v=get_val(p);
    return v[1]>0;
}

//2MB
pii arr[200010];


void task(){
    int n;//2e5 6e5
    read(n);
    for(int i=1;i<=n;i++){
        read(al[i][0]);
        read(al[i][1]);
        read(bl[i][0]);
        read(bl[i][1]);
    }
    pool_top=0;
    root=alloc();
    for(int i=1;i<=n;i++){
        range_add_p2(bl[i][1]+1,E91,al[i][1],-al[i][0]);
        range_add_p2(bl[i][0],bl[i][1]+1,al[i][1],al[i][1]);
        range_add_p2(1,bl[i][0],-al[i][0],al[i][1]);
    }
    int rl=0;
    int rr=0;
    int l=1;
    int r=E9;
    while(l<r){
        int mid=(l+r)>>1;
        if(checkl(mid)){
            r=mid;
        }else{
            l=mid+1;
        }
    }
    rl=l;
    l=1;
    r=E9;
    while(l<r){
        int mid=(l+r+1)>>1;
        if(checkr(mid)){
            l=mid;
        }else{
            r=mid-1;
        }
    }
    rr=l;
    for(int i=1;i<=n;i++){
        arr[i-1]={bl[i][0],bl[i][1]};
    }
    sort(arr,arr+n);
    int res=0;
    int lst=rl-1;
    for(int i=0;i<n;i++){
        pii v=arr[i];
        int l=max(lst+1,v.first);
        int r=min(v.second,rr);
        if(r>=l){
            res+=r-l+1;
            lst=r;
        }
    }
    writeln(res);
}


int main(){
    freopen("lucky.in","r",stdin);
    freopen("lucky.out","w",stdout);
    // ios::sync_with_stdio(false);
    int c,t;
    read(c);
    read(t);
    for(int i=0;i<t;i++){
        task();
    }
    fclose(stdin);
    fclose(stdout);
    return 0;
}