#include <algorithm>
#include <bitset>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstring>
#include <ctime>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <vector>
#define ll long long
#define lf double
#define eps 1e-8
#define inf (1ll << 60)
#define pi 3.1415926535897932
#define _pb push_back
#define _mp make_pair
#define _1 first
#define _2 second
#define MAX_N 10000//int最大
#define maxn 1145//maxn做数组大小
using namespace std;
typedef long long LL;
struct coord {
	int x, y;
};
queue<coord>Q;
int ans[maxn][maxn], death[maxn][maxn];
int wk[4][2] = {{0, 1}, {1, 0}, {-1, 0}, {0, -1}};//方向函数
int main() {
	int m, Ans = MAX_N;
	memset(ans, -1, sizeof(ans));
	memset(death, 0x7f, sizeof(death));
	scanf("%d", &m);
	for (int i = 1; i <= m; i++) {
		int x, y, t;
		scanf("%d %d %d", &x, &y, &t);
#define MIN(x,y,t) if(x>=0 && y>=0) death[x][y] = min(death[x][y],t)
		MIN(x, y, t);
		for (int k = 0; k < 4; k++)
			MIN(x + wk[k][0], y + wk[k][1], t);
	}
	Q.push((coord) {
		0, 0
	});//压入地图
	ans[0][0] = 0;
	while (!Q.empty()) {
		coord u = Q.front();
		int ux = u.x, uy = u.y;
		Q.pop();
		for (int k = 0; k < 4; k++) {//Bessie走的路
			int x = ux + wk[k][0], y = uy + wk[k][1];
			if (x < 0 || y < 0 || ans[x][y] != -1 || ans[ux][uy] + 1 >= death[x][y])
				continue;//剪枝
			ans[x][y] = ans[ux][uy] + 1;
			Q.push((coord){x,y});//将x,y（扩展的位置）压入栈
		}
	}
	for(int i=0;i<=305;i++)
		for(int j = 0; j <= 305; j++)//整个地图判断
			if(death[i][j]> 1000 && ans[i][j] != -1)//只要不成立
				Ans = min(Ans,ans[i][j]);
	if(Ans ==MAX_N)
		puts("-1");
	else
		printf("%d",Ans);
	return 0;
}