Ternary search#10169

Ternary search

1 second
128 megabytes
Very easy

Find the minimum of the function f(x) = x^2 + ax + b.

Input

Two integers and b~(|a|, |b| \le 10^6).

Output

Print the value of for which the function attains its minimum. Print the answer with exactly two digits after the decimal point. It is guaranteed that |x| \le 100.

Examples

Example 1

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