#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; using namespace atcoder; typedef long long ll; typedef long double ld; typedef std::pair pii; typedef std::pair pil; typedef std::pair pli; typedef std::pair pll; typedef std::pair pid; typedef std::pair pis; typedef std::pair pls; typedef std::vector vb; typedef std::vector vvb; typedef std::vector vi; typedef std::vector vvi; typedef std::vector vvvi; typedef std::vector vvvvi; typedef std::vector vl; typedef std::vector vvl; typedef std::vector vvvl; typedef std::vector vvvvl; typedef std::vector vd; typedef std::vector vvd; typedef std::vector vs; #define rep(i,n) for(auto i=0; i=0; --i) #define repdm(i,e,n) for(auto i=n-1; i>=e; --i) #define all(a) (a).begin(), (a).end() #define rall(a) (a).rbegin(), (a).rend() template inline bool chmax(T& a, T b, int eq = 0) { if (a < b || (a == b && eq)) { a = b; return 1; } return 0; } template inline bool chmin(T& a, T b, int eq = 0) { if (a > b || (a == b && eq)) { a = b; return 1; } return 0; } template * = nullptr> constexpr istream& operator>>(istream& is, mint& x) noexcept {long long v = 0; std::cin >> v; x = v; return is;} template * = nullptr> constexpr ostream& operator<<(ostream& os, const mint& x) noexcept {os << x.val(); return os;} inline void _n() { std::cout << std::endl; } template inline void _(const T a) { std::cout << a; } template inline void _l(const T a) { _(a); _n(); } template inline void _s(const T a) { _(a); _(' '); } template inline void _v(const std::vector v) { for(auto a : v) _(a); } template inline void _vl(const std::vector v) { for(auto a : v) _l(a); } template inline void _vs(const std::vector v) { for(auto a : v) _s(a); _n(); } template inline void _vvl(const std::vector> v) { for(auto a : v) { _v(a); _n(); } } template inline void _vvs(const std::vector> v) { for(auto a : v) { _vs(a); } } inline void ynl(const bool b) {_l(b ? "yes" : "no");} inline void yns(const bool b) {_l(b ? "Yes" : "No");} inline void ynu(const bool b) {_l(b ? "YES" : "NO");} constexpr int INF = numeric_limits::max() >> 1; constexpr long long INF_LL = numeric_limits::max() >> 1LL; constexpr long long MOD1 = 1000000007; constexpr long long MOD9 = 998244353; using mint1 = atcoder::modint1000000007; using mint9 = atcoder::modint998244353; //* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *// void solve() { int N, M; cin >> N >> M; M -= 2; vvi mat(N, vi(N, -1)); vvi used(N, vi(N)); mat[0][0] = mat[N-1][N-1] = 1; used[0][0] = 1; int di[4] = {1, 0, -1, 0}; int dj[4] = {0, 1, 0, -1}; queue que; que.push({0, 0}); while(!que.empty()) { int qi, qj; tie(qi, qj) = que.front(); que.pop(); used[qi][qj] = 1; rep(k, 4) { int ni = qi + di[k]; int nj = qj + dj[k]; if(ni == N-1 && nj == N-1) {yns(1); return;} if(!(0 <= ni && ni < N && 0 <= nj && nj < N)) continue; if(used[ni][nj] == 1) continue; used[ni][nj] = 1; _s(ni+1); _l(nj+1); string S; cin >> S; if(S == "Black") { mat[ni][nj] = 1; if(M-- == 0) {yns(0); return;} que.push({ni, nj}); } else if(S == "White") { mat[ni][nj] = 0; } else { return; } } } yns(mat[N-1][N-1] == 1); } //* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *// int main() { std::ifstream in("input.txt"); std::cin.rdbuf(in.rdbuf()); std::cin.tie(0); std::cout.tie(0); std::ios::sync_with_stdio(false); solve(); return 0; }