Poj Solution 2521

http://poj.org/problem?id=2521

    import java.util.*;  
      
    public class Main {  
      
        public static void main(String[] args) {  
            Scanner cin = new Scanner(System.in);  
            while(cin.hasNext())  
            {  
                String tmp = cin.nextLine();  
               if(tmp.equals("0 0 0 0"))  
                   break;  
               String[] tmp1 = tmp.split(" ");  
               int N = Integer.valueOf(tmp1[0]);  
               int M = Integer.valueOf(tmp1[1]);  
               int P = Integer.valueOf(tmp1[2]);  
               int C = Integer.valueOf(tmp1[3]);  
                 
               int totalPaid = M + C;  
              int totalTrue = totalPaid - P;  
                 
               int earn = totalTrue - N - C;  
                
              System.out.println(earn*-1);  
                 
           }  
    
       }  
     
   }