Given function f(x, y) = ax² + bxy + cy², check if f(x, y)≤ 0 holds for all x, y ∈ R.

The input contains zero or more test cases and is terminated by end-of-file.
Each test case contains three integers a, b, c.
• −10≤ a, b, c ≤ 10
• The number of tests cases does not exceed 10⁴.

For each case, output “Yes” if f(x, y) ≥0 always holds. Otherwise, output “No”.

1 -2 1
1 -2 0
0 0 0

Yes
No
Yes

2017年四川省赛