#include <bits/stdc++.h>
using namespace std;

typedef pair<int,int> PII;
int m,t[1010],step[310][310];
PII star[50010];
queue<PII> q;

int dx[] = {0,0,-1,1};
int dy[] = {1,-1,0,0};

bool checkMove(int x,int y,int curTime)//检查是否可以移动到(x,y),curTime为当前时刻 
{
	if(x < 0 || y < 0 || step[x][y] != -1) return false;
	for(int i = 1;i <= m;i++)
	{
		if(abs(x - star[i].first) <= 1 && y == star[i].second && curTime >= t[i]) return false;
		if(abs(y - star[i].second) <= 1 && x == star[i].first && curTime >= t[i]) return false;
	}
	return true;
}

bool checkSec(int x,int y)//检查是否安全 
{
	for(int i = 1;i <= m;i++)
	{
		if(abs(x - star[i].first) <= 1 && y == star[i].second) return false;
		if(abs(y - star[i].second) <= 1 && x == star[i].first) return false;
	}
	return true;
}

int main()
{
	cin >> m;
	for(int i = 1;i <= m;i++)
	{
		cin >> star[i].first >> star[i].second >> t[i];
	}
	//bfs
	memset(step,-1,sizeof(step));
	q.push({0,0});
	step[0][0] = 0;
	while(!q.empty())
	{
		PII b = q.front();
		q.pop();
		for(int i = 0;i < 4;i++)
		{
			PII a = b;
			a.first += dx[i];
			a.second += dy[i];
			if(checkMove(a.first,a.second,step[b.first][b.second] + 1))
			{
				q.push(a);
				step[a.first][a.second] = step[b.first][b.second] + 1;
				if(checkSec(a.first,a.second))
				{
					cout << step[a.first][a.second];
					return 0;
				}
			}
		}
	}
	cout << "-1";
	return 0;
}