#include using namespace std; #define REP(i,n) for(ll i=0;i<(ll)n;i++) #define dump(x) cerr << "Line " << __LINE__ << ": " << #x << " = " << (x) << "\n"; #define spa << " " << #define fi first #define se second #define ALL(a) (a).begin(),(a).end() #define ALLR(a) (a).rbegin(),(a).rend() using ld = long double; using ll = long long; using ull = unsigned long long; using pii = pair; using pll = pair; using pdd = pair; template using V = vector; template using P = pair; template vector make_vec(size_t n, T a) { return vector(n, a); } template auto make_vec(size_t n, Ts... ts) { return vector(n, make_vec(ts...)); } template ostream& operator << (ostream& os, const pair v){os << "(" << v.first << ", " << v.second << ")"; return os;} template ostream& operator<<(ostream &os, const vector &v) { for (auto &e : v) os << e << ' '; return os; } template ostream& operator<<(ostream& os, const vector> &v){ for(auto &e : v){os << e << "\n";} return os;} struct fast_ios { fast_ios(){ cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_; template void UNIQUE(vector &x) {sort(ALL(x));x.erase(unique(ALL(x)), x.end());} template bool chmax(T &a, const T &b) { if (a bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; } void fail() { cout << -1 << '\n'; exit(0); } inline int popcount(const int x) { return __builtin_popcount(x); } inline int popcount(const ll x) { return __builtin_popcountll(x); } template void debug(vector>&v,ll h,ll w){for(ll i=0;i void debug(vector&v,ll n){if(n!=0)cerr<> N >> M; auto ask = [](ll a, ll b)->ll{ cout << a+1 << " " << b+1 << endl; string T; cin >> T; if(T == "Black"){ return 1; }else if(T == "White"){ return 0; }else{ assert(1); } return -1; }; auto answer = [](bool flag){ cout << (flag ? "Yes" : "No") << endl; exit(0); }; const int num_dir = 4; const int dx[] = {0, -1, 0, 1}; const int dy[] = {1, 0, -1, 0}; const int H = N; const int W = N; vector> dist(H, vector(W, -1)); queue> qu; qu.emplace(0, 0); dist[0][0] = 0; // BFS ll cnt = 0; while(!qu.empty()){ auto p = qu.front();qu.pop(); for(int idx=0;idxH-1 or nj>W-1) continue; if(dist[ni][nj] != -1) continue; if(cnt > 3000){ answer(false); } ll bw = ask(ni, nj); cnt++; if(bw == 1){ dist[ni][nj] = dist[p.first][p.second] + 1; qu.emplace(ni, nj); }else{ dist[ni][nj] = -2; } } } answer(false); //debug(dist, H, W); return 0; }