import java.util.*;
import java.lang.*;
import java.io.*;
 
class Brovko
{
	public static void main (String[] args) throws java.lang.Exception
{
	double sum=0, a; 	
	Scanner in = new Scanner(System.in);
	while(in.hasNext())
	{
		a = in.nextDouble();
		if (a<0)
		{
			break;
		}
		sum+=a;
	}
		System.out.format("Сумма членов последовательности до первого отрицательного элемента равна %5.1f \n",sum);
}
}

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NC4yIDMuMiAxIC01IDEgNQ==

4.2 3.2 1 -5 1 5