#include<bits/stdc++.h>
using namespace std;
#define maxn 310
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}};
int main(){
	int m, Ans = 100000;
	memset(ans, -1, sizeof(ans));
	memset(death, 0x7f, sizeof(death));
	cin >> m;
	for(int i = 1;i <= m;i++){
		int x, y, t;
		cin >> 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});
	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++){
			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;
			ans[x][y] = ans[ux][uy] + 1;
			Q.push((coord){x, y});
		}
	}
	for(int i = 0;i <= 305;i++){
		for(int j = 0;j <= 305;j++){
			if(death[i][j] > 1000 && ans[i][j] != -1)
				Ans = min(Ans, ans[i][j]);
		}
	}
	if(Ans == 100000) puts("-1");
	else printf("%d", Ans);

	return 0;
}