import std.stdio, std.conv, std.functional, std.string; import std.algorithm, std.array, std.container, std.range, std.typecons; import std.bigint, std.numeric, std.math, std.random; import core.bitop; string FMT_F = "%.10f"; static File _f; void file_io(string fn) { _f = File(fn, "r"); } static string[] s_rd; T _RD(T = long)() { while(!s_rd.length) s_rd = readln.chomp.split; string res = s_rd[0]; s_rd.popFront; return res.to!T; } T _RD(T = long)(File f) { while(!s_rd.length) s_rd = f.readln.chomp.split; string res = s_rd[0]; s_rd.popFront; return res.to!T; } T[] _RDA(T = long)(T fix = 0) { auto r = readln.chomp.split.to!(T[]); r[] += fix; return r; } T[] _RDA(T = long)(File f, T fix = 0) { auto r = f.readln.chomp.split.to!(T[]); r[] += fix; return r; } T RD(T = long)() { if (_f.isOpen) return _RD!T(_f); else return _RD!T; } T[] RDA(T = long)(T fix = 0) { if (_f.isOpen) return _RDA!T(_f, fix); else return _RDA!T(fix); } size_t[] MAKE_IDX(alias less = "a < b", Range)(Range range) { auto idx = new size_t[](range.length); makeIndex!(less)(range, idx); return idx;} size_t MIN_POS(alias less = "a < b", Range)(Range range) { auto r = minPos!(less)(range); return range.length - r.length; } void chmin(T)(ref T x, T y) { x = min(x, y); } void chmax(T)(ref T x, T y) { x = max(x, y); } bool inside(T)(T x, T b, T e) { return x >= b && x < e; } T lcm(T)(T x, T y) { return x * (y / gcd(x, y)); } //long mod = 10^^9 + 7; long mod = 998_244_353; //long mod = 1_000_003; void moda(T)(ref T x, T y) { x = (x + y) % mod; } void mods(T)(ref T x, T y) { x = ((x + mod) - (y % mod)) % mod; } void modm(T)(ref T x, T y) { x = (x * y) % mod; } void modpow(T)(ref T x, T y) { if (!y) { x = 1; return; } auto t = x; x.modpow(y>>1); x.modm(x); if (y&1) x.modm(t); } void modd(T)(ref T x, T y) { x.modm(y.modpow(mod - 2)); } void main() { auto N = RD; auto M = RD; auto edges = new long[][](N); foreach (i; 0..M) { auto a = RD-1; auto b = RD-1; auto c = RD; edges[a] ~= b; if (c == 1) edges[b] ~= a; } bool ans; auto state = new long[](N); state[] = 10^^7; auto par = new long[](N); par[] = -1; debug writeln(state); (){ foreach (i; 0..N) { long[] open = [i]; while (!open.empty) { auto from = open.front; open.popFront; if (state[from] == i) { debug writeln("from:", from, " i:", i, " state[from]:", state[from]); ans = true; return; } else if (state[from] < i) continue; state[from] = i; foreach (to; edges[from]) { if (to != par[from]) { par[to] = from; open ~= to; } } } }}(); writeln(ans ? "Yes" : "No"); stdout.flush; debug readln; }