s=[input() for i in range(3)]
flag=True
for i in range(3):
    for j in range(3):
        if i<2:
            if s[i+1][j]==s[i][j]:
                flag=False
                break
    if j<2:
        if s[i][j+1]==s[i][j]:
            flag=False
            break
if flag:
    print("Yes")
else:
    print("No")