#pragma GCC optimize("O3") #include using namespace std; using ll=long long; using P=pair; template using V=vector; #define fi first #define se second #define all(v) (v).begin(),(v).end() const ll inf=(1e18); //const ll mod=998244353; const ll mod=1000000007; const vector dy={-1,0,1,0},dx={0,-1,0,1}; ll GCD(ll a,ll b) {return b ? GCD(b,a%b):a;} ll LCM(ll c,ll d){return c/GCD(c,d)*d;} struct __INIT{__INIT(){cin.tie(0);ios::sync_with_stdio(false);cout< bool chmax(T &a, const T &b) { if (a bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; } templatevoid debag(const vector &a){cerr<<"debag :";for(auto v:a)cerr<void print(const vector &a){for(auto v:a)cout< par,num; int find(int v){ return (par[v]==v)? v: (par[v]=find(par[v])); } explicit UF(){} explicit UF(int N):par(N),num(N,1){ iota(all(par),0); } void init(int N){ par.assign(N,0); num.assign(N,1); iota(all(par),0); } void unite(int u,int v){ u=find(u),v=find(v); if(u==v)return; if(num[u]; int main(){ int n,m; cin>>n>>m; V d(m); for(int i=0;i>d[i].se.fi>>d[i].se.se>>d[i].fi; d[i].se.fi--; d[i].se.se--; } UF uf(n); sort(all(d),greater()); ll ma=inf; V> g(n); for(int i=0;id[i].fi)break; g[d[i].se.fi].emplace_back(d[i].se.se); g[d[i].se.se].emplace_back(d[i].se.fi); uf.unite(d[i].se.fi,d[i].se.se); if(uf.same(0,n-1)){ ma=d[i].fi; } } V dp(n,int(1e7)); dp[0]=0; queue q; q.emplace(0); while(q.size()){ int cur=q.front(); q.pop(); for(int v:g[cur]){ if(chmin(dp[v],dp[cur]+1)){ q.emplace(v); } } } cout<