#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N=2010;
int n,ans;
struct Point
{
    int x,y;
    friend inline Point operator + (const Point &a,const Point &b) {return (Point){a.x+b.x,a.y+b.y};}
    friend inline Point operator - (const Point &a,const Point &b) {return (Point){a.x-b.x,a.y-b.y};}
    friend inline int operator * (const Point &a,const Point &b) {return a.x*b.y-a.y*b.x;}
    friend inline bool operator == (const Point &a,const Point &b) {return (a.x==b.x)&(a.y==b.y);}
};
struct Line
{
    Point a,b;
}a[N];

int sign(int x)
{
    if(x<0) return -1;
    if(x>0) return 1;
    return 0;
}

int work(Point A,Point B)
{
    int ans=0;
    for(int i=1;i<=n;i++)
        if(sign((a[i].a-A)*(B-A))*sign((a[i].b-A)*(B-A))!=1) ans+=abs(a[i].b.x-a[i].a.x);
    return ans;
}

signed main(void)
{
    scanf("%lld",&n);
    for(int i=1;i<=n;i++) 
    {
        int x0,x1,y;
        scanf("%lld%lld%lld",&x0,&x1,&y);
        a[i]=(Line){(Point){x0,y},(Point){x1,y}};
    }
    for(int i=1;i<=n;i++)
        for(int j=i+1;j<=n;j++)
            if(a[i].a.y!=a[j].a.y) ans=max({ans,work(a[i].a,a[j].a),work(a[i].a,a[j].b),work(a[i].b,a[j].a),work(a[i].b,a[j].b)});
    printf("%lld\n",ans);
    
    return 0;
}