public class Main
{
public static double distanza( double x1 , double y1 , double x2 , double y2 )
{
return Math.sqrt( Math.pow(x1-x2,2.0) + Math.pow(y1-y2,2.0) ) ;
}
public static void main(String[] args)
{
System.out.println( distanza(0.0,0.0,3.0,4.0) ) ;
}
}