#include using namespace std; template struct xor_dsu { public: xor_dsu() : _n(0) {} xor_dsu(int n) : _n(n), num_component(n), parent_or_size(n, -1), diff_weight(n) {} bool merge(int a, int b, T w) { assert(0 <= a && a < _n); assert(0 <= b && b < _n); int x = leader(a), y = leader(b); w ^= diff_weight[a] ^ diff_weight[b]; if(x == y) return w == 0; if (-parent_or_size[x] < -parent_or_size[y]) std::swap(x, y); parent_or_size[x] += parent_or_size[y]; parent_or_size[y] = x; diff_weight[y] = w; num_component--; return true; } T diff(int a, int b) { if(!same(a, b)) return -1; return diff_weight[a] ^ diff_weight[b]; } bool same(int a, int b) { assert(0 <= a && a < _n); assert(0 <= b && b < _n); return leader(a) == leader(b); } int leader(int a) { assert(0 <= a && a < _n); if (parent_or_size[a] < 0) return a; int r = leader(parent_or_size[a]); diff_weight[a] ^= diff_weight[parent_or_size[a]]; return parent_or_size[a] = r; } int size() { return num_component; } int size(int a) { assert(0 <= a && a < _n); return -parent_or_size[leader(a)]; } std::vector> groups() { std::vector leader_buf(_n), group_size(_n); for (int i = 0; i < _n; i++) { leader_buf[i] = leader(i); group_size[leader_buf[i]]++; } std::vector> result(_n); for (int i = 0; i < _n; i++) { result[i].reserve(group_size[i]); } for (int i = 0; i < _n; i++) { result[leader_buf[i]].push_back(i); } result.erase( std::remove_if(result.begin(), result.end(), [&](const std::vector& v) { return v.empty(); }), result.end()); return result; } private: int _n, num_component; std::vector parent_or_size; std::vector diff_weight; }; int main(){ ios::sync_with_stdio(false); cin.tie(0); int n, m, u, v; cin >> n >> m; xor_dsu uf(n); for(int i = 0; i < m; i++){ cin >> u >> v; if(!uf.merge(--u, --v, 1)){ cout << "No\n"; return 0; } } cout << "Yes\n"; }