s = [list(input()) for _ in range(3)]
boo = True
for i in range(3):
    for j in range(3):
        if i+j == 0:
            continue
        if (i+j)%2:
            if s[0][0] == s[i][j]:
                boo = False
        else:
            if s[0][0] != s[i][j]:
                boo = False

print("Yes" if boo else "No")