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Background

Description

二次方程 ax2+bx+c = 0 (其中a≠0），a 是二次项系数，bx 叫作一次项，b是一次项系数；c叫作常数项。 x 的值为：

根的判别式

Format

Input

Output

Samples

1 1 -2

1
-2

1 -10 25

5
5

1 2 3

-1+1.41421i
-1-1.41421i

Limitation