import java.util.Scanner; 
public class Main{ 
    public static void main(String[] args) { 
         Scanner scan = new Scanner(System.in); 
         int n = scan.nextInt();
         int i;
         Truck tr = new Truck();
         for(i = 0; i < n; i++) {
        	 int number = scan.nextInt();
        	 int weight = scan.nextInt();
        	 if(number == 1) {
        		 Appliance app = new TV(weight);
        		 tr.add(app);
        	 }
        	 else if(number == 2) {
        		 Appliance app = new WashMachine(weight);
        		 tr.add(app);
        	 }
        	 else {
        		 Appliance app = new AirConditioner(weight);
        		 tr.add(app);
        	 }
         }
         System.out.println(tr.getTWeight());
         
         scan.close();  
    } 
}  

class Appliance{
	private int weight;
	public Appliance(int wei) {
		weight = wei;
	}
	public int getWeight(){
		return weight;
	}
}

class TV extends Appliance{
	public TV(int wei) {
		super(wei);
	}
	public int getWeight(){
		return super.getWeight();
	}
}

class WashMachine extends Appliance{
	public WashMachine(int wei) {
		super(wei);
	}
	public int getWeight() {
		return super.getWeight();
	}
}

class AirConditioner extends Appliance{
	public AirConditioner(int wei) {
		super(wei);
	}
	public int getWeight() {
		return super.getWeight();
	}
}

class Truck{
	private static int sum = 0;
	public Truck() {
	}
	public void add(Appliance a) {
		sum += a.getWeight();
	}
	public int getTWeight() {
		return sum;
	}
}