#define _CRT_SECURE_NO_WARNINGS #define _USE_MATH_DEFINES #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; typedef long double ld; typedef long long ll; typedef vector vint; typedef vector vll; typedef pair pii; typedef pair pll; typedef pair pdd; typedef complex compd; #define quickIO() {cin.tie(0); cout.sync_with_stdio(false);} #define reach(i,a) for(auto i:a) #define rep(i,n) for(int i=0;i<((int)n);i++) #define REP(i,n) for(int i=0;i<=((int)n);i++) #define srep(i,a,n) for(int i=a;i<((int)n);i++) #define SREP(i,a,n) for(int i=a;i<=((int)n);i++) #define rrep(i,n) for(int i=n-1;i>=0;i--) #define RREP(i,n) for(int i=n;i>=0;i--) #define all(a) (a).begin(),(a).end() #define mp(a,b) make_pair(a,b) #define mt make_tuple #define pb push_back template istream& operator >> (istream& is, vector& vec) { for (T& x : vec) is >> x; return is; } template ostream& operator << (ostream& os, vector& vec) { os << "["; rep(i, vec.size()) os << (i ? ", " : "") << vec[i]; os << "]"; return os; } template istream& operator >> (istream& is, pair& p) { is >> p.first >> p.second; return is; } template ostream& operator << (ostream& os, pair& p) { os << p.first << " " << p.second; return os; } template bool operator < (vector& a, vector& b) { rep(i, a.size()) { if (i == b.size()) return false; if (a[i] < b[i]) return true; else if (a[i] > b[i]) return false; } return false; } template bool operator > (vector& a, vector& b) { rep(i, a.size()) { if (i == b.size()) return true; if (a[i] < b[i]) return false; else if (a[i] > b[i]) return true; } return false; } int bitcnt(ll x) { x = ((x & 0xAAAAAAAAAAAAAAAA) >> 1) + (x & 0x5555555555555555); x = ((x & 0xCCCCCCCCCCCCCCCC) >> 2) + (x & 0x3333333333333333); x = ((x & 0xF0F0F0F0F0F0F0F0) >> 4) + (x & 0x0F0F0F0F0F0F0F0F); x = ((x & 0xFF00FF00FF00FF00) >> 8) + (x & 0x00FF00FF00FF00FF); x = ((x & 0xFFFF0000FFFF0000) >> 16) + (x & 0x0000FFFF0000FFFF); x = ((x & 0xFFFFFFFF00000000) >> 32) + (x & 0x00000000FFFFFFFF); return x; } int bitcnt(int x) { x = ((x & 0xAAAAAAAA) >> 1) + (x & 0x55555555); x = ((x & 0xCCCCCCCC) >> 2) + (x & 0x33333333); x = ((x & 0xF0F0F0F0) >> 4) + (x & 0x0F0F0F0F); x = ((x & 0xFF00FF00) >> 8) + (x & 0x00FF00FF); x = ((x & 0xFFFF0000) >> 16) + (x & 0x0000FFFF); return x; } ll sqrtll(ll x) { ll left = 0, right = x; rep(i, 100) { ll mid = (left + right) >> 1; if (mid * mid <= x) left = mid; else right = mid; } return left; } ll gcd(ll a, ll b) { return b == 0 ? a : gcd(b, a % b); } #define debug(x) printf("Case #%d: ", x) #undef DEBUG const ld infl = 1e100; const ll mod = 998244353; const ld eps = 1e-9; const ll inf = 1e15; const int dx[] = { 1,0,-1,0,1, -1 }; const int dy[] = { 0,1,0,-1,1, -1 }; int group[100000]; int parent(int i) { return group[i] = (group[i] == i ? i : parent(group[i])); } void merge(int i, int j) { i = parent(i); j = parent(j); group[i] = j; } int main() { int n, m; cin >> n >> m; vector d_edge; rep(i, n) group[i] = i; rep(i, m) { int a, b, c; cin >> a >> b >> c; a--; b--; if (c == 1) { if (parent(a) == parent(b)) { cout << "Yes" << endl; return 0; } else merge(a, b); } else d_edge.push_back(mp(a, b)); } vint deg(n); vector edge(n); for (auto e : d_edge) { edge[parent(e.first)].push_back(parent(e.second)); } rep(i, n) { for (int to : edge[i]) { deg[to]++; } } queue q; int cnt = 0; rep(i, n) { if (i == parent(i)) { cnt++; if (deg[i] == 0) { q.push(i); cnt--; } } } while (!q.empty()) { int it = q.front(); q.pop(); for (int to : edge[it]) { if (--deg[to] == 0) { q.push(to); cnt--; } } } cout << (cnt ? "Yes" : "No") << endl; return 0; }