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#include <bits/stdc++.h>
#define all(x) x.begin(),x.end()
#define CLR(i,a) memset(i,a,sizeof(i))
#define fi first
#define se second
#define pb push_back
#define SZ(a) ((int) a.size())
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define ROF(i, a, b) for (int i = (a); i >= (b); --i)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef __int128 i128;
typedef pair<ll,ll> pll;
typedef array<ll,2> arr;
typedef double DB;
typedef pair<DB,DB> pdd;
typedef pair<ll,bool> plb;
constexpr ll MAXN=static_cast<ll>(1e6)+10,INF=static_cast<ll>(1e18)+3;
constexpr ll mod=static_cast<ll>(1e9)+7;
constexpr double eps=1e-8;
ll N,M,K,T;
vector<ll> g[MAXN];
struct DSU {
vector<int> fa, siz;
int ln;
DSU(int n) {
ln = n;
fa.resize(ln + 5, 0), siz.resize(ln + 5, 0);
FOR(i, 1, n) {
fa[i] = i;
siz[i] = 1;
}
}
int find(int x) {
while (fa[x] != x) {
x = fa[x];
fa[x] = fa[fa[x]];
}
return x;
}
bool same(int x, int y) { return find(x) == find(y); }
bool merge(int x, int y) {
x = find(x);
y = find(y);
if (x == y) {
return false;
}
siz[x] += siz[y];
fa[y] = x;
return true;
}
int size(int x) { return siz[find(x)]; }
int countFa() {
int res = 0;
FOR(i, 1, ln) {
if (fa[i] == i) ++res;
}
return res;
}
};
inline void solve(){
cin>>N>>M;
DSU dsu(N);
FOR(i,1,M){
ll u,v;
cin>>u>>v;
if(u>v) swap(u,v);
g[u].pb(v);
g[v].pb(u);
dsu.merge(u,v);
}
if(dsu.countFa()!=1){
cout<<"No\n";
return;
}
if(M==N){
FOR(i,1,N){
if(SZ(g[i])!=2){
cout<<"No\n";
return;
}
}
cout<<"Yes\n";
}else{
cout<<"No\n";
}
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(0);cout.tie(0);
solve();
return 0;
}
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