#include<bits/stdc++.h>
using namespace std;
#define maxn 301
struct coord{
    int x,y;
};
queue<coord>Q;
int ans[maxn][maxn],death[maxn][maxn];
int walk[4][2]={{-1,0},{0,1},{1,0},{0,-1}};
int main(){
    int m,x,y,t,ANS=1e5;
    memset(ans,-1,sizeof(ans));
    memset(death,0x7f,sizeof(death));
    cin>>m;
    for(int i=1;i<=m;i++){
        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+walk[k][0],y+walk[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+walk[k][0],y=uy+walk[k][1];
            if(x<0||y<0||ans[x][y]!=-1||death[x][y]<=ans[ux][uy]+1){
                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!=1e5) cout<<ANS;
    else cout<<"-1";
    return 0;
}