#include using namespace std; struct iofast_t { iofast_t() { ios::sync_with_stdio(false); cin.tie(nullptr); } } iofast; struct uns_t {} uns; template auto vec(Element init, Head arg, Args ...args) { if constexpr (sizeof...(Args) == 0) return vector(arg, init); else return vector(arg, vec(init, args...)); } template auto vec(uns_t, Head arg, Args ...args) { return vec(Element(), arg, args...); } template auto distance(const Container &c, decltype(begin(c)) iter) { return distance(begin(c), iter); } template ::value_type>> auto isort(RIter first, RIter last, Compare comp = Compare()) { vector i(distance(first, last)); iota(begin(i), end(i), 0); sort(begin(i), end(i), [&](auto x, auto y) { return comp(*(first + x), *(first + y)); }); return i; } template typename, typename = void_t<>> struct detect : false_type {}; template typename Check> struct detect>> : true_type {}; template typename Check> constexpr inline bool detect_v = detect::value; template using has_member_sort = decltype(declval().sort()); template > auto sorted(Container c, Compare comp = Compare()) { if constexpr (detect_v) { c.sort(comp); return c; } else { sort(begin(c), end(c), comp); return c; } } template > auto uniqued(Container c, Compare comp = Compare()) { c.erase(unique(begin(c), end(c), comp), end(c)); return c; } template > T &chmin(T &l, T r, Compare &&f = less()) { return l = min(l, r, f); } template > T &chmax(T &l, T r, Compare &&f = less()) { return l = max(l, r, f); } template constexpr auto fix(F &&f) noexcept { return [f = std::tuple(std::forward(f))](auto &&...args) mutable { return std::get<0>(f)(fix(std::get<0>(f)), std::forward(args)...); }; } #include #include using mint = atcoder::modint998244353; int main() { int n, q; cin >> n >> q; auto info = vec>(uns, q); for (auto &[a, b, c] : info) { cin >> a >> b >> c; --a; --b; } atcoder::dsu dsu(n); for (auto [a, b, c] : info) { if (c == 0) { dsu.merge(a, b); } } for (auto [a, b, c] : info) { if (c == 1) { if (dsu.same(a, b)) { cout << 0 << endl; return 0; } } } auto led = vec(uns, 0); for (int i = 0; i < n; ++i) { led.push_back(dsu.leader(i)); } led = uniqued(sorted(move(led))); auto comp = [&](int v) { return distance(led, lower_bound(begin(led), end(led), v)); }; auto g = vec>(uns, size(led)); for (auto [a, b, c] : info) { a = comp(dsu.leader(a)); b = comp(dsu.leader(b)); if (c == 1) { g[a].insert(b); g[b].insert(a); } } mint ans = 1; auto col = vec(-1, size(led)); for (int i = 0; i < size(led); ++i) { if (0 <= col[i]) { continue; } auto f = fix([&](auto f, int v, int c = 0) -> bool { if (0 <= col[v]) { return (c != col[v]); } col[v] = c; for (auto u : g[v]) { if (f(u, !c)) { return true; } } return false; })(i); if (f) { cout << 0 << endl; return 0; } ans *= 2; } cout << ans.val() << endl; }