package lectures.loops;
import util.annotations.WebDocuments;

import java.io.DataInputStream;
@WebDocuments({"Lectures/Loops.pptx", "Lectures/Loops.pdf", "Videos/Loops.avi"})
public class SentinelBasedFoldingNumberMultiplier {
    static DataInputStream dataIn = new DataInputStream (System.in);
    
    public static void main (String args[]) {
        int intNum = 1;
        int nextNum = readNumber();
            while (nextNum >= 0) {
                intNum *= nextNum;
                nextNum = readNumber();
        }
        print(intNum);
        pause();
    }
    
    public static int readNumber() {    
        return readInt();
    }
    
    public static int readInt() {
        try {
            return Integer.parseInt(dataIn.readLine());
        } catch (Exception e) {
            return 0;
        }   
    }
    
    public static void print(int total) {
        System.out.println(total);
    }
    
    public static void pause() {
        try {
            System.in.read();
        } catch (Exception e) {
            System.out.println(e);
        }
    }
}