from collections import deque n, m = map(int, input().split()) sx, sy = 0, 0 gx, gy = n - 1, n - 1 INF = 10 ** 18 def bfs(): d = [[-1] * n for i in range(n)] dx = [1, 0, -1, 0] dy = [0, 1, 0, -1] que = deque([]) que.append((sy, sx)) d[sy][sx] = 0 while que: p = que.popleft() if p[0] == gy and p[1] == gx: exit(print("Yes")) for i in range(4): nx = p[0] + dx[i] ny = p[1] + dy[i] if nx == n - 1 and ny == n - 1: exit(print("Yes")) if 0 <= nx < n and 0 <= ny < n and d[nx][ny] == -1: print(nx + 1, ny + 1) res = input() if res == "Black": que.append((nx, ny)) d[nx][ny] = 0 break else: d[nx][ny] = 1 return d[gy][gx] print("Yes" if bfs() == 0 else "No")