// see https://github.com/LumaKernel/vimfiles/tree/master/snippets/cp-cpp/temp.snip const bool DEBUG = 1; /// --- .lumrc Template {{{ /// #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; using ll = long long; using ull = unsigned long long; using ld = long double; using P = tuple; using P3 = tuple; using VI = vector; using VL = vector; using VP = vector

; using VS = vector; #define omajinai ios::sync_with_stdio(false);cin.tie(0) #define FOR(i,a,b) for(int i=int(a);i=int(a);--i) #define RFORI(i,a,b) for(int i=int(b);i>=int(a);--i) #define RREP(i,n) RFOR(i,0,n) #define RREPI(i,n) RFORI(i,0,n) #define ALL(a) (a).begin(),(a).end() #define UNIQUE(a) (a).erase(unique(ALL(a)),(a).end()) #define PB push_back #define EACH(i,c) REP(i,(c).size()) #define REACH(i,c) RREP(i,(c).size()) #define EXIST(s,e) ((s).find(e)!=(s).end()) #define SORT(c) sort(ALL(c)) #define BR cout<<"\n"; #define dump(x) if(DEBUG) cerr<<"["<<__LINE__<< "] "<<#x<<"="<<(x)<<"\n"; #define dump2(x,y) if(DEBUG) cerr<<"["<<__LINE__<< "] "<<#x<<"="<<(x)\ <<" , "<<#y<<"="<<(y)<<"\n"; #define dump3(x,y,z) if(DEBUG)cerr<<"["<<__LINE__<<"] "<<#x<<"="<<(x)\ <<" , "<<#y<<"="<<(y)\ <<" , "<<#z<<"="<<(z)<<"\n"; #define SAY(x) if(DEBUG) cerr<<"["<<__LINE__<< "] "<<(x)<<"\n"; #define YES(x) cout<<((x)?"YES":"NO")<<"\n"; #define Yes(x) cout<<((x)?"Yes":"No")<<"\n"; #define yes(x) cout<<((x)?"yes":"no")<<"\n"; inline int omajinai_int_in(){omajinai;int n;cin>>n;return n;} inline ll omajinai_ll_in(){omajinai;ll n;cin>>n;return n;} inline string omajinai_string_in(){omajinai;string n;cin>>n;return n;} inline int int_in(){int n;cin>>n;return n;} inline ll ll_in(){ll n;cin>>n;return n;} inline string string_in(){string n;cin>>n;return n;} #define oini omajinai_int_in() #define oinl omajinai_ll_in() #define oins omajinai_string_in() #define ini int_in() #define inl ll_in() #define ins string_in() #define isInside(y,x) (0<=(y)&&(y)(x)) #define se(x) (get<1>(x)) #define th(x) (get<2>(x)) #define fo(x) (get<3>(x)) #define fif(x) (get<4>(x)) template ostream &operator<<(ostream &o, const vector &v) { o << '['; EACH(i, v) o << v[i] << (i != v.size()-1 ? ", " : ""); o << "]"; return o; } template inline void smax(T &a, T b) { a = a > b ? a : b; } template inline void smin(T &a, T b) { a = a < b ? a : b; } /// }}}--- /// constexpr int INF = 1e9+1; constexpr ll LINF = 1e18+1; constexpr int MOD = 1e9+7; ll ans; int main() { int n=ini,m=ini; int nn = n/2; // n-1 <= m <= n/2 * (n+1)/2 // n-1 <= m <= nn * (n-nn) if(n-1 > m || m > nn * (n-nn)) { cout << "NO" << endl; return 0; } VP es; es.reserve(m); int p = m - (n-1); REP(i, nn) { es.PB(P(i, i+nn)); if(i+nn+1= n) break; if(j == i+nn || j == i+nn+1) { j++; continue; } es.PB(P(i, j)); j++; p--; } } cout << "YES" << endl; REP(i, n-1) cout << i+1 << " "; cout << n << endl; for(auto el:es) { cout << fi(el)+1 << " " << se(el)+1 << endl; } } //