package week12day3;

import java.util.InputMismatchException;
import java.util.Scanner;

public class Sum {
	public static void main(String[] args){
		Scanner input = new Scanner(System.in);
		int sum = 0;
		while(true){
			int answer;
			try{
				answer = input.nextInt();	
			}catch(InputMismatchException ime){
				answer = 12;
				input.next();
			}
			if(answer < 0)
				break;
			sum += answer;
		}
		System.out.println(sum);
		input.close();
	}
}