piecewise function

Write a program to evaluate the following piecewise function y=f(x).

y=-x+2.5; 0 <= x < 5

y=2-1.5(x-3)(x-3); 5 <= x < 10

y=x/2-1.5; 10 <= x < 20
input
a floating point number N, 0 <= N < 20
output
output N corresponding piecewise function value: f(N). The result is rounded to three decimal places.
Example input
1.0

Sample output
1.500

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        float f;
        double sum = 0;
        Scanner scan=new Scanner(System.in);
        f=scan.nextFloat();
        if(f>=0 && f<5)
            sum=-f+2.5;
        else if(f>=5 && f<10)
            sum=2-1.5*(f-3)*(f-3);
        else if(f>=10 && f<20)
            sum=f/2-1.5;
        System.out.println(String.format("%.3f",sum));
    }

}