#include<bits/stdc++.h> using namespace std; const int maxn = 5e5 + 10; int n, m, x, y, w, cnt, col[maxn], dis[maxn], vis[maxn], d[maxn], head[maxn]; struct node{ int nxt, to, val; }e[maxn << 1]; void add(int x, int y, int w){ e[++cnt].to = y; e[cnt].nxt = head[x]; head[x] = cnt; e[cnt].val = w; } queue<int> q; int main(){ scanf("%d%d", &n, &m); for(int i = 1; i <= m; ++i){ scanf("%d%d%d", &x, &y, &w); add(y, x, w); } if(n == 1){ printf("0\n0"); return 0; } memset(col, -1, sizeof(col)); q.push(n); vis[n] = 0; while(q.size()){ int x = q.front(); q.pop(); if(x == 1)break; for(int i = head[x]; i; i = e[i].nxt){ int v = e[i].to; if(vis[v])continue; if(col[v] == -1 || col[v] == e[i].val ^ 1)col[v] = e[i].val ^ 1; else{//有两种颜色 q.push(v); d[v] = d[x] + 1; vis[v] = 1; } } } if(d[1])printf("%d\n", d[1]); else printf("-1\n"); for(int i = 1; i <= n; ++i){ if(col[i] == -1)printf("0"); else printf("%d", col[i]); } return 0; }