import java.io.*;
class ReadNumbersFromFile
{
    public static void main(String[] args) 
    {
        try{
        BufferedReader br=new BufferedReader(new FileReader("input.txt"));
        String str="";
        int sum=0;
        while((str=br.readLine())!=null){
            int num=Integer.parseInt(str);
            sum+=num;
        }
        br.close();
        BufferedWriter bw=new BufferedWriter(new FileWriter("output.txt"));
        bw.write(Integer.toString(sum));
        bw.close();
        System.out.println("Data has been written in the file.");
        }
        catch(Exception E){}
    }
}