import sys sys.setrecursionlimit(10**6) int1 = lambda x: int(x)-1 p2D = lambda x: print(*x, sep="\n") def II(): return int(sys.stdin.buffer.readline()) def LI(): return list(map(int, sys.stdin.buffer.readline().split())) def LI1(): return list(map(int1, sys.stdin.buffer.readline().split())) def LLI(rows_number): return [LI() for _ in range(rows_number)] def LLI1(rows_number): return [LI1() for _ in range(rows_number)] def BI(): return sys.stdin.buffer.readline().rstrip() def SI(): return sys.stdin.buffer.readline().rstrip().decode() # dij = [(0, 1), (-1, 0), (0, -1), (1, 0)] # dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)] dij = [(0, 1), (1, 0), (1, 1), (1, -1)] inf = 10**19 # md = 998244353 md = 10**9+7 class UnionFind: def __init__(self, n): self.state = [-1]*n self.size_table = [1]*n # cntはグループ数 self.cnt = n def root(self, u): v = self.state[u] if v < 0: return u self.state[u] = res = self.root(v) return res def merge(self, u, v): ru = self.root(u) rv = self.root(v) if ru == rv: return du = self.state[ru] dv = self.state[rv] if du > dv: ru, rv = rv, ru if du == dv: self.state[ru] -= 1 self.state[rv] = ru self.cnt -= 1 self.size_table[ru] += self.size_table[rv] return # グループの要素数 def size(self, u): return self.size_table[self.root(u)] from collections import defaultdict n, m = LI() uf = UnionFind(n) to = [[] for _ in range(n)] deg = [0]*n for _ in range(m): u, v, c = LI1() if c: to[u].append(v) else: uf.merge(u, v) deg[u] += 1 deg[v] += 1 rtou = defaultdict(list) for u in range(n): r = uf.root(u) rtou[r].append(u) gtou = list(rtou.values()) utog = [0]*n for g, uu in enumerate(gtou): e = 0 for u in uu: utog[u] = g e += deg[u] if e//2 > len(uu)-1: print("Yes") exit() gn = len(gtou) to2 = [set() for _ in range(gn)] for u in range(n): g = utog[u] for v in to[u]: to2[g].add(utog[v]) def dfs(g): stack = [g] while stack: g = stack.pop() if fin[g] == -1: fin[g] = 0 stack.append(g) for v in to2[g]: if fin[v] == -1: stack.append(v) elif fin[v] == 0: return True elif fin[g] == 0: fin[g] = 1 return False fin = [-1]*gn for g in range(gn): if fin[g] == -1 and dfs(g): print("Yes") exit() print("No")