A group of people played a game. All players had distinct scores, which are positive integers.

Takahashi knows N facts on the players' scores. The i-th fact is as follows: the A_i-th highest score among the players is B_i.

Find the maximum possible number of players in the game.

Constraints

* 1 \leq N \leq 10^5
* 1 \leq A_i \leq 10^9(1\leq i\leq N)
* 0 \leq B_i \leq 10^9(1\leq i\leq N)
* If i ≠ j, A_i ≠ A_j.
* There exists a possible outcome of the game that are consistent with the facts.
* All input values are integers.

Inputs

Input is given from Standard Input in the following format:


N
A_1 B_1
:
A_N B_N


Outputs

Print the maximum possible number of players in the game.

Examples

Input

3
4 7
2 9
6 2


Output

8


Input

5
1 10
3 6
5 2
4 4
2 8


Output

7


Input

2
1 1000000000
1000000000 1


Output

1000000001
import java.util.Arrays;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		Main main = new Main();
		People[] people = new People[N];
		for (int i = 0; i < N; i++) {
			People p = main.new People();
			p.a = sc.nextInt();
			p.b = sc.nextInt();
			people[i] = p;
		}
		Arrays.parallelSort(people);
		int count =0;
//		count +=people[0].a-1;
		count +=people[N-1].b+people[N-1].a;
		System.out.println(count);
	}

	public class People implements Comparable<People> {
		int a;
		int b;
		@Override
		public int compareTo(People o) {
			return this.a - o.a;
		}

	}
}