3669

/*
宽度优先搜索

啥时候才能杜绝小错误呢，以后ij一定不在搞混了
*/

// include file
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cctype>
#include <ctime>

#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <bitset>
#include <strstream>

#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <set>
#include <list>
#include <functional>

using namespace std;

// typedef
typedef long long LL;
typedef unsigned long long ULL;

// 
#define read freopen("in.txt","r",stdin)
#define write freopen("out.txt","w",stdout)
#define FORi(a,b,c) for(int i=(a);i<(b);i+=c)
#define FORj(a,b,c) for(int j=(a);j<(b);j+=c)
#define FORk(a,b,c) for(int k=(a);k<(b);k+=c)
#define FORp(a,b,c) for(int p=(a);p<(b);p+=c)

#define FF(i,a)    for(int i=0;i<(a);i+++)
#define FFD(i,a)   for(int i=(a)-1;i>=0;i--)
#define Z(a) (a<<1)
#define Y(a) (a>>1)

const double eps = 1e-6;
const double INFf = 1e10;
const int INFi = 1000000000;
const double Pi = acos(-1.0);

template<class T> inline T sqr(T a){return a*a;}
template<class T> inline T TMAX(T x,T y)
{
	if(x>y) return x;
	return y;
}
template<class T> inline T TMIN(T x,T y)
{
	if(x<y) return x;
	return y;
}
template<class T> inline void SWAP(T &x,T &y)
{
	T t = x;
	x = y;
	y = t;
}
template<class T> inline T MMAX(T x,T y,T z)
{
	return TMAX(TMAX(x,y),z);
}


// code begin
#define MAXN 410
int mp[MAXN][MAXN];
int used[MAXN][MAXN];
int N;
struct node
{
	node(){}
	node(int a,int b,int t)
	{
		s=a;
		e=b;
		tm=t;
	}
	int s;
	int e;
	int tm;
};
queue<node> qn;
int dir[5][2] = {1,0,0,1,-1,0,0,-1,0,0};

int main()
{
	read;
	write;
	int x,y,t;
	while(scanf("%d",&N)!=-1)
	{
		memset(mp,-1,sizeof(mp));
		FORi(0,N,1)
		{
			scanf("%d %d %d",&x,&y,&t);
			
			FORj(0,5,1)
			{
				int xx = x+dir[j][0];
				int yy = y+dir[j][1];
				if( xx>=0 && xx<MAXN && yy>=0 && yy<MAXN)
				{
					if(mp[yy][xx]==-1) mp[yy][xx] = t;
					else mp[yy][xx] = TMIN(mp[yy][xx],t);
				}
			}
		}

		// BFS
		if(mp[0][0]==0)
		{
			printf("-1\n");
		}
		else
		{
			while(!qn.empty()) qn.pop();
			qn.push(node(0,0,0));
			memset(used,-1,sizeof(used));
			used[0][0]= 0;
			int ans = -1;
			while(!qn.empty())
			{
				node cur = qn.front();
				qn.pop();

				FORi(0,4,1)
				{
					x = cur.s + dir[i][0];
					y = cur.e + dir[i][1];
					if( x>=0 && x<MAXN && y>=0 && y<MAXN)
					{
						if(mp[y][x]==-1)
						{
							ans = cur.tm+1;
							break;
						}
						if(cur.tm+1<mp[y][x] && (used[y][x]==-1 || cur.tm+1<used[y][x]) )
						{
							used[y][x] = cur.tm+1;
							qn.push(node(x,y,cur.tm+1));
						}
					}
				}
				if(ans!=-1) break;
			}
			printf("%d\n",ans);
		}
	}
	return 0;
}