#include //#include //#include //#include #define rep(i, a) for (int i = (int)0; i < (int)a; ++i) #define rrep(i, a) for (int i = (int)a - 1; i >= 0; --i) #define REP(i, a, b) for (int i = (int)a; i < (int)b; ++i) #define RREP(i, a, b) for (int i = (int)a - 1; i >= b; --i) #define repl(i, a) for (ll i = (ll)0; i < (ll)a; ++i) #define pb push_back #define eb emplace_back #define all(x) x.begin(), x.end() #define rall(x) x.rbegin(), x.rend() #define popcount __builtin_popcount #define popcountll __builtin_popcountll #define fi first #define se second using ll = long long; constexpr ll mod = 1e9 + 7; constexpr ll mod_998244353 = 998244353; constexpr ll INF = 1LL << 60; // #pragma GCC target("avx2") // #pragma GCC optimize("O3") // #pragma GCC optimize("unroll-loops") //using lll=boost::multiprecision::cpp_int; //using Double=boost::multiprecision::number>;//仮数部が1024桁 template inline bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; } template inline bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; } ll mypow(ll x, ll n, const ll &p = -1) { //x^nをmodで割った余り if (p != -1) { x =(x%p+p)%p; } ll ret = 1; while (n > 0) { if (n & 1) { if (p != -1) ret = (ret * x) % p; else ret *= x; } if (p != -1) x = (x * x) % p; else x *= x; n >>= 1; } return ret; } using namespace std; //using namespace atcoder; struct edge{ int to,cost; edge(int a,int b):to(a),cost(b){} }; void solve() { int n,m; cin>>n>>m; vector>g(n); rep(i,m){ int s,t,d; cin>>s>>t>>d; s--;t--; g[s].eb(t,d); g[t].eb(s,d); } vectormaxv(n); maxv[0]=INT_MAX; auto dfs=[&g,&maxv](auto self,int v)->void{ for(auto x:g[v]){ if(chmax(maxv[x.to],min(maxv[v],x.cost))){ self(self,x.to); } } }; dfs(dfs,0); vectordis(n,-1); dis[0]=0; int ans=maxv.back(); auto dfs2=[&g,ans,&dis](auto self,int v)->void{ for(auto x:g[v]){ if(dis[x.to]==-1&&x.cost>=ans){ dis[x.to]=dis[v]+1; self(self,x.to); } } }; dfs2(dfs2,0); int ans2=dis.back(); cout<