#include int main() { using namespace std; cin.tie(nullptr)->sync_with_stdio(false); int n, m; cin >> n >> m; vector a(n, vector(n, -1)); a[0][0] = 1; a[n - 1][n - 1] = 1; auto query = [&](int i, int j) -> bool { cout << i + 1 << ' ' << j + 1 << endl; if (a[i][j] != -1) return a[i][j]; string s; cin >> s; return (a[i][j] = s[0] == 'b'); }; constexpr array di{1, 0, -1, 0}; constexpr array dj{0, 1, 0, -1}; vector visited(n, vector(n)); auto dfs = [&](auto self, int i, int j) -> void { if (i == n - 1 && j == n - 1) { cout << "Yes" << endl; exit(0); } for (int d : {0, 1, 2, 3}) { int ni = i + di[d]; int nj = j + dj[d]; if (min(ni, nj) < 0 || max(ni, nj) >= n || !query(ni, nj)) continue; if (visited[ni][nj]) continue; visited[ni][nj] = true; self(self, ni, nj); } }; visited[0][0] = true; dfs(dfs, 0, 0); cout << "No" << endl; }