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.Scanner;

public class Main{
	
	public static void main(String[] args){
		
		Scanner sc =new Scanner(System.in);
		
		int N =sc.nextInt();
		int[] ar =new int[N];
		int[] br =new int[N];
		
		for(int i=0;i<N;i++){
			ar[i] = sc.nextInt();
			br[i] = sc.nextInt();			
		}
		int min=0;
		
		int m1=br[0];
		for(int i=1;i<N;i++){
			m1 = Math.min(m1,br[i]);
		}
		
		int count=0;
		
		for(int i=1;i<N;i++){
			if(m1==br[i]) count=i;
		}
		int result=ar[count]+br[count];
				
		System.out.println(result);

		
		
	}

}
