// >>> TEMPLATES #include using namespace std; using ll = long long; using ld = long double; using i32 = int32_t; using i64 = int64_t; #define int ll #define double ld #define rep(i,n) for (int i = 0; i < (int)(n); i++) #define rep1(i,n) for (int i = 1; i <= (int)(n); i++) #define repR(i,n) for (int i = (int)(n)-1; i >= 0; i--) #define rep1R(i,n) for (int i = (int)(n); i >= 1; i--) #define loop(i,a,B) for (int i = a; i B; i++) #define loopR(i,a,B) for (int i = a; i B; i--) #define all(x) (x).begin(), (x).end() #define allR(x) (x).rbegin(), (x).rend() #define pb push_back #define eb emplace_back #define mp make_pair #define fst first #define snd second auto constexpr INF32 = numeric_limits::max()/2-1; auto constexpr INF64 = numeric_limits::max()/2-1; auto constexpr INF = numeric_limits::max()/2-1; #ifdef LOCAL #include "debug.hpp" #define dump(...) cerr << "[" << setw(3) << __LINE__ << ":" << __FUNCTION__ << "] ", dump_impl(#__VA_ARGS__, __VA_ARGS__) #define say(x) cerr << "[" << __LINE__ << ":" << __FUNCTION__ << "] " << x << endl #define debug if (1) #else #define dump(...) (void)(0) #define say(x) (void)(0) #define debug if (0) #endif template using pque_max = priority_queue; template using pque_min = priority_queue, greater >; template ::value>::type> ostream& operator<<(ostream& os, T const& v) { bool f = true; for (auto const& x : v) os << (f ? "" : " ") << x, f = false; return os; } template ::value>::type> istream& operator>>(istream& is, T &v) { for (auto& x : v) is >> x; return is; } template istream& operator>>(istream& is, pair& p) { return is >> p.first >> p.second; } struct IOSetup { IOSetup() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); } } iosetup; template struct FixPoint : private F { constexpr FixPoint(F&& f) : F(forward(f)) {} template constexpr auto operator()(T&&... x) const { return F::operator()(*this, forward(x)...); } }; struct MakeFixPoint { template constexpr auto operator|(F&& f) const { return FixPoint(forward(f)); } }; #define MFP MakeFixPoint()| #define def(name, ...) auto name = MFP [&](auto &&name, __VA_ARGS__) template struct vec_impl { using type = vector::type>; template static type make_v(size_t n, U&&... x) { return type(n, vec_impl::make_v(forward(x)...)); } }; template struct vec_impl { using type = T; static type make_v(T const& x = {}) { return x; } }; template using vec = typename vec_impl::type; template auto make_v(Args&&... args) { return vec_impl::make_v(forward(args)...); } template void quit(T const& x) { cout << x << endl; exit(0); } template constexpr bool chmin(T& x, U const& y) { if (x > y) { x = y; return true; } return false; } template constexpr bool chmax(T& x, U const& y) { if (x < y) { x = y; return true; } return false; } template constexpr auto sumof(It b, It e) { return accumulate(b,e,typename iterator_traits::value_type{}); } template int sz(T const& x) { return x.size(); } template int lbd(C const& v, T const& x) { return lower_bound(v.begin(), v.end(), x)-v.begin(); } template int ubd(C const& v, T const& x) { return upper_bound(v.begin(), v.end(), x)-v.begin(); } template int ppt(C const& v, F f) { return partition_point(v.begin(), v.end(), f)-v.begin(); } // <<< // >>> union find struct UnionFind { int n, sz; // id : 0...n-1 vector par; UnionFind(int n = 0) : n(n), sz(n), par(n,-1) { } int root(int x) { assert(0 <= x); assert(x < n); return par[x] < 0 ? x : par[x] = root(par[x]); } bool unite(int x, int y) { x = root(x), y = root(y); if (x == y) return false; sz--; if (par[x] < par[y]) swap(x,y); par[y] += par[x]; par[x] = y; return true; } bool same(int x, int y) { return root(x) == root(y); } int size(int x) { return -par[root(x)]; } int size() const { return sz; } struct groups_t { vector > grp; vector > id; }; groups_t groups() { vector > g(n); rep (i,n) if (par[i] < 0) g[i].reserve(-par[i]); rep (i,n) g[root(i)].push_back(i); vector > grp; grp.reserve(size()); rep (i,n) if (g[i].size()) grp.emplace_back(move(g[i])); vector > id(n); rep (i,grp.size()) rep (j,grp[i].size()) { id[grp[i][j]] = make_pair(i,j); } return { grp, id }; } }; // <<< // >>> scc constexpr int dst(int v) { return v; } template constexpr int dst(E const& e) { return e.to; } template struct SCC { vector > const& g; vector ord, low, st; int32_t time = 0, pos = 0, sz = 0; SCC(vector > const& g) : g(g), ord(g.size()), low(g.size()), st(g.size()) { rep (v,g.size()) if (ord[v] == 0) dfs(v); for (auto &x : ord) x += sz; } void dfs(int v) { low[v] = ord[v] = ++time; st[pos++] = v; for (auto const& e : g[v]) { if (ord[dst(e)] == 0) { dfs(dst(e)); chmin(low[v], low[dst(e)]); } else if (ord[dst(e)] > 0) { chmin(low[v], ord[dst(e)]); } } if (low[v] == ord[v]) { sz++; do ord[st[--pos]] = -sz; while (st[pos] != v); } } int size() const { return sz; } int id(int v) const { return ord[v]; } vector > groups() const { vector > grp(sz); rep (v,g.size()) grp[ord[v]].push_back(v); return grp; } }; template auto get_scc(vector > const& g) { return SCC(g); } // <<< int32_t main() { int n,m; cin >> n >> m; vector a(m),b(m),c(m); rep (i,m) cin >> a[i] >> b[i] >> c[i], --a[i],--b[i]; UnionFind uf(n); rep (i,m) if (c[i] == 1) { if (uf.same(a[i],b[i])) quit("Yes"); uf.unite(a[i],b[i]); } auto grp = uf.groups(); vector> g(uf.size()); rep (i,m) if (c[i] == 2) { int x = grp.id[a[i]].fst; int y = grp.id[b[i]].fst; if (x == y) quit("Yes"); g[x].eb(y); } auto scc = get_scc(g); cout << (scc.size() < sz(g) ? "Yes" : "No") << endl; }