J02009

/*
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 * Click nbfs://nbhost/SystemFileSystem/Templates/Other/File.java to edit this template
 */
package withouclass;

import java.util.Collections;
import java.util.Comparator;
import java.util.Scanner;
import java.util.Vector;

class Pair {
    public int t;
    public int d;

    void input(Scanner sc) {
        t = sc.nextInt();
        d = sc.nextInt();
    }
}

public class J02009 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        Vector<Pair> v = new Vector<>();
        for (int i = 0; i < n; i++) {
            Pair x = new Pair();
            x.input(sc);
            v.add(x);
        }
        Collections.sort(v, new Comparator<Pair>() {
            @Override
            public int compare(Pair a, Pair b) {
                if (a.t > b.t)
                    return 1;
                else
                    return -1;
            }
        });
        int s = 0;
        for (int i = 0; i < n; i++) {
            if (s < v.get(i).t)
                s = v.get(i).t;
            s += v.get(i).d;
        }
        System.out.println(s);
        sc.close();
    }
}